Another tank flushing question?

[sandy43]

After reading about a few folks with water problems because of the vacuum breaker valve in the tanks flushing system, I talked to a person last night who has a rather new Montana (I assume Alpine has the same set-up) and he had the same problem about water in the bathroom area. His dealer told him if he closes the black tank valve when the flushing system is on and operating somethings got to give and usually it's the fittings, mainly the one that's connected to the vacuum breaker valve. He admitted, rather his wife did, that he closed the valve on the black tank thinking it would clean it better. Could this be why several people had a water problem? I'm trying to learn this system the best I can. Sorry for the long rant. Thanks

[laidback]

I close mine for 2 or 3 min then open it back up and have never had a problem. I don't think I would leave it closed until the tank got full. If it got to full it would have to go somewhere, but being only a few gal it should be at the bottom of the tank.

[golfpro]

I shut the valve when using mine. I installed it half way up the wall and I listen to when the water noise changes and then open the valve and let the water out and all the black it washes off the walls. If you let it stay closed then you are asking for trouble.

[hankaye]

sandy43, Howdy;

I got rid of the cheap POS valve that came with the trailer. It came apart when I used it the first time. I replaced it with a simple elbow.

I do close the valve when flushing out the black tank. I don't even consider any form of multi-tasking when it's dump time. I'll keep the valve closed for 3 minutes then pull the 'T'-handle repete. Then I disconnect the flush hose. close the tank valve. I'll go inside and fill the tank with the foot valve. Then go outside and pull the 'T'-handle one last time. Back inside I drop 2 scoops of oxy-clean and 2 caps of downey to the empty tank and fill the bowel 3 times so any new 'deposits' have something to swim in...

hankaye

[webslave]

Closing your black tank valve shouldn't have any effect; don't know why a dealer would say otherwise, unless he has no idea how a vacuum breaker works. I've always used the black tank valve to "add water" to increase flow when emptying the black tank with no ill effects.

Picture an inverted "V" (/\) with the vacuum breaker at the top. It basically is a pressure operated valve. As long as there is water pressure on the valve, the valve closes off the vent and passes water through the "V" and into the tank. Even with the tank full, the pressure should keep the valve closed. When pressure is totally removed, i.e., the ends of the flush line are open to atmosphere, the valve will open (no pressure holding it closed) allowing water to flow back down both sides of the "/\", but, due to gravity, not up and over the "/\". That's why it is a "vacuum breaker"...breaks the vacuum caused by the downhill flow of water from its highest point (that's why they are located so high, usually under the bathroom sink, uphill from both the water inlet and the flusher).

Several things can cause those valves to leak...age (the seals deteriorate), broken components (age or just, most likely, a cheaply built unit), or contaminates in the water that prevent a good seal and over pressurization. Most of us, at sometime or another will have to deal with the usually cheap component aspect and replace the unit with a better made unit. I, personally, haven't ever had an issue with any of them on my trailers and the only thought I have on that is that I use the same filtered water as I drink...I have a whole house filter that removes sediment and chemicals and I use that same filtered water in my flushers; I also limit the water pressure to 40 psi. I have a Watts regulator that takes the CG water pressure down to 60 psi and I use a second pressure regulator on my flusher hose to further reduce it to 40 psi for use with the flushers... Or it could be that I'm just incredibly lucky"bouncey:

[SmittysRV]

Okay good to hear you can run the santi flush with the valve is closed...... it says right on mine to make sure the valves are always open when using the santi flush. I thought that using the santi flush with the valve closed will just fill the black tank and assist with the flow when emptying. I also use the pressure regulator when using the santi flush, just never knew if I needed to. Thx

[webslave]

Most manufacturers and accessory manufacturers (those that manufacture add-on tank flushers) will tell you not to use them with the waste gates closed...my guess would be a liability avoidance should you forget and let the flusher run until the tank gets "over filled". Nasty things can happen when water is forced into a virtually closed environment (the rules of hydraulics apply...the vent stack will take some, but, you wouldn't believe the pressure developed in the tank as that happens; the vent is designed to vent "fumes" not liquid). I've heard tales of ruptured tanks, broken toilets, etc.

As long as you only leave it closed for a minute or so, if you start with the tank almost empty, you aren't doing anything more than "a long flush" with the toilet by adding water in that fashion. Just be mindful of the time ;)

[albertr]

My vacuum breaker fell apart. Dollar Store quality item.

[allentx1]

I also close my valve when flushing. About 3-4 minutes is all I can tolerate without worrying. I have yet to have an issue with the leakage as mentioned, maybe it's just the luck of the draw.

[Quiroule]

OK, I am new to this.

Where is the vacuum valve located and does it do for me.

[SteveC7010]

OK, I am new to this.

Where is the vacuum valve located and does it do for me.

There are already several extensive threads on the vacuum breaker, its probable location, and its function. Search on vacuum breaker to find them.

In short, if you have the factory installed black tank sprayer/flush system, the water line goes from the connection up, usually into the bathroom under the sink to a vacuum breaker and then down to the flush/sprayer inside the black water holding tank.

The purpose of the vacuum breaker is to prevent a siphoning action which could back feed black water into the fresh water hose connected to the flush system. The vacuum breaker needs to be several feet above the black water tank and the shore line connection to work properly.

[geo]

Steve is quite correct - several times we have fallen into the vacuum of the black tank vacuum breaker. Here's one of those threads with a diagram:

http://www.keystonerv.org/forums/showthread.php?t=4656&highlight=vacuum

If you looks in Mods, you will find a post from Geo describing how and why I replaced my vacuum breaker with a 200# WOG anti-back flush valve.

Ron

[Patrick Ely]

Another problem with my Montana! I was flushing the black tank and found water leaking out in the pocket door and bathroom area. I found that the vacuum break was leaking. The great part of this is that it is located where there is no access! I had to cut a hole in the pantry paneling to get to it. Wonderful engineering! That is the second hole I had to cut since the pocket door also fell from the ceiling after a short trip. There is no way to access this without removing the shower! And all of this with less than 3000 miles of towing!

[chuckster57]

Another problem with my Montana! I was flushing the black tank and found water leaking out in the pocket door and bathroom area. I found that the vacuum break was leaking. The great part of this is that it is located where there is no access! I had to cut a hole in the pantry paneling to get to it. Wonderful engineering! That is the second hole I had to cut since the pocket door also fell from the ceiling after a short trip. There is no way to access this without removing the shower! And all of this with less than 3000 miles of towing!

Often times, and it may not be in your case, if the vacuum breaker is behind the shower all you have to remove is the faucet assembly.

[Scalemaster]

Mine was located in the wall behind a small panel above the toilet. I cut it completely out and direct connected it from the connection point to the black tank. I added an anti siphon valve to the hose connection point. I can't imagine the damage this would have caused if it filled the interior of the wall with water.

[Jimbeau]

You need to be VERY CAUTIOUS when adding water to the black tank with the valve closed. This guy we camped with accidentally put the fresh water hose onto the black tank flusher, walked away, then saw "water" leaking profusely from the bottom of the 5th wheel. The pressure had built up and it blew out his black tank (for a nice $850 repair!!). After seeing that I had my wife color the flushers cap with red nail polish and no more confusion when your trying to rush to get hooked up.
When mine was (luckily) still under warranty the vaccum breaker check valve on mine actually blew out and started leaking water all over outside. My RV guy said it was happening on a lot of trailers, and replaced it with a plain elbow bend. The only difference is you need two hoses, one dedicated "dirty water" for flushing and another for "fresh water".

[dcg9381]

So I don't entirely understand the function of the valve. I always thought that these were designed like homes, basically that plumbing was "vented" to the roof. Why is a check valve necessary for air flow?


Clearly the recommendation is not to flush with the valves closed, but I've been doing that for years - perhaps now I know why I shouldn't?

I assume if you want to get a good flush of that tank, you need to feed water in from the top to fill it from the top via non-pressurized means?

I learn something on this forum every day...

[SteveC7010]

So I don't entirely understand the function of the valve. I always thought that these were designed like homes, basically that plumbing was "vented" to the roof. Why is a check valve necessary for air flow?

Clearly the recommendation is not to flush with the valves closed, but I've been doing that for years - perhaps now I know why I shouldn't?

I assume if you want to get a good flush of that tank, you need to feed water in from the top to fill it from the top via non-pressurized means?

I learn something on this forum every day...
It's not blocking air flow, it's blocking the flow of liquid. The vacuum breaker on the black flush line prevents any possibility of a back flow of contaminated water into your hose and possibly into the plumbing of where ever you are getting your water. It is an anti-siphon device.

If you remove the vacuum breaker, it's essential that you use an anti-siphon bib on your hose that you connect to the black tank flush. IMHO, it should be placed on the end of the hose connecting to the trailer's fitting.

[Quiroule]

I too thought that the black water tank was vented to the roof. If not, where is-it vented?

[SteveC7010]

I too thought that the black water tank was vented to the roof. If not, where is-it vented?
It is vented to the roof. The black tank flush system has nothing to do with the venting of the black tank. As I just said in my previous post, the vacuum breaker in the black tank flush plumbing is an anti-siphon device.

[dcg9381]

So the whole warning to not flush a tank with the valve closed is to simply prevent a liquid overflow condition?

[Javi]

So the whole warning to not flush a tank with the valve closed is to simply prevent a liquid overflow condition?
Well.... yeah or a busted fitting or weak seam... truth is, although the tank is vented out the top... if you over fill it enough that it forces water up the vent pipe you are putting a lot of pressure on the tank and associated fittings. Some of those fittings aren't glued it but are snapped in. POW.. :eek:


It don't hurt nothing to use the flush with the dump valve closed... until you forget it and pop a fitting or a seam.. :D

[SteveC7010]

Well.... yeah or a busted fitting or weak seam... truth is, although the tank is vented out the top... if you over fill it enough that it forces water up the vent pipe you are putting a lot of pressure on the tank and associated fittings. Some of those fittings aren't glued it but are snapped in. POW.. :eek:
In older TT's where the toilet was literally just a few inches above the top of the black tank, overfilling under pressure via the black flush could very easily result in a broken toilet and a very nasty geyser in the bathroom.

The other possibility in some of the rigs where the second toilet and a bathroom sink both feed the black tank is that it could easily push stuff up through the p-trap into the sink.

Just another reason to make sure the vent pipes are always clear.

Liquid under pressure takes the shortest path of least resistance.

I would also point out that folks tend to not use pressure regulators on the hoses that they use for the black tank flush. There's a good argument for a bit of extra pressure for a stronger "blast" in this situation, but that also reinforces the need to do so with the drain valve open.

[SteveC7010]

So the whole warning to not flush a tank with the valve closed is to simply prevent a liquid overflow condition?
As Javi affirmed, that is the intent. But understand the facts behind the warning.

1. Black (and gray) holding tanks are just that. They are not manufactured to contain pressure above normal atmospheric and the weight of the contents.

2. The black tank flush uses hose pressure to drive a little sprinkler kind of nozzle in the tank. The pressure makes the nozzle move randomly about which directs the pressure of the spray everywhere in the tank. That hopefully will result in a nice clean tank.

3. As I mentioned in the previous post, folks have a tendency not to use a pressure regulator on the hose they connect to the black tank flush port. That means that instead of 40 psi max, one could be applying as much as 80 or 90 psi to the flush. I do it myself, especially at home.

4. If you close the drain gate and the liquid rises above the nozzle, you've killed the pressure and motion action. A lot of us will close the gate for a couple of minutes to build up enough liquid in the tank to float away any remaining solids. Generally we don't let the tank fill so much that we can no longer hear the nozzle blasting the walls of the tank.

5. Ultimately, if you close that gate and allow the tank to fill, you've now placed the tank under pressures that it is not built to withstand AND you have the full weight of a full tank in there. (Mine is 36x8.4 which equals about 302 pounds of water. Some of you have bigger holding tanks.) Too much pressure plus all that weight is a recipe for a serious failure.

6. Keystone was notorious for using chintzy vacuum breakers which would break under minimal stress. If you fill the tank with the flush running, you're placing undue strain on the device. If you've already bypassed the vacuum breaker and are using one of the less expensive anti-siphon bibs, it could be similarly stressed. In this case, the vacuum breaker piping then acts as a siphon and things begin to get messy.

My whole point here is to help folks understand that if they choose to take a shortcut, they should have all the facts before doing so. Black tank and drain line leaks are the absolute worst to deal with during a camping trip

[Face Down]

So I don't entirely understand the function of the valve.

From what I understand it is installed to keep a siphon situation from happening and sending contamination back into the water system ....but it seems to me this is very unlikely. For this to happen...


Your black tank would need to be full up to where the spray nozzle is located.
With the tank full, a hose hooked up to the Flush System
All valves on the water system open
Water system loses all pressure
Then and only then, could a siphon happen.


Since I only use the spray system once the tank is empty and open...it could not happen with what my procedure is for flushing the tanks.

I have deleted both of the vacuum breakers on my unit (2 black tanks) and replaced with elbows. I do not use any type of anti-siphon on the hose. Last week was the first time used since I made the change and the system works great now! ;)

[SteveC7010]

From what I understand it is installed to keep a siphon situation from happening and sending contamination back into the water system ....but it seems to me this is very unlikely. For this to happen...


Your black tank would need to be full up to where the spray nozzle is located.
With the tank full, a hose hooked up to the Flush System
All valves on the water system open
Water system loses all pressure
Then and only then, could a siphon happen.


Since I only use the spray system once the tank is empty and open...it could not happen with what my procedure is for flushing the tanks.

I have deleted both of the vacuum breakers on my unit (2 black tanks) and replaced with elbows. I do not use any type of anti-siphon on the hose. Last week was the first time used since I made the change and the system works great now! ;)
I don't believe that there is a pressure check valve on the black flush hose connection. If that is the case, and I am certain that at least some of the rigs don't have them, then there is the possibility of a back flow anytime the liquid level in the tank covers the nozzle. Those that remove the vacuum breaker and replace it with an elbow still have some anti-siphon protection because of the high loop of the plumbing that drains itself when not in use. Those that remove the loop and have a direct line to the tank have a greater risk of back flow because it is only a few inches above the top of the tank at most. It would only take a small momentary build-up of pressure in the black tank to push liquid back through the flush. It's a remote possibility, I agree, but worth taking into account.

It may be possible for a back flow through the flush plumbing which would just pour out of the connection when there is no hose attached for flushing. Since a lot of these connections are now in compartments, that could generate a real mess all on its own.

I am not saying that folks shouldn't make these mods, but rather trying to put all the facts on the table so that people can make fully informed decisions about these things.

FWIW, my black flush is unaltered only because the vacuum breaker has not broken, yet. I am pretty sure my rig is one that does not have a check valve on the black water flush port because I get a good bit of fresh water back when I disconnect the hose. Either that or the check valve is there and has locked in the open position. That fresh water draining out of the piping is one point where a siphon could take place under ideal conditions. (If there is a check valve, it's not doing its job. I should take things apart and see what's what. Might be the ideal time to remove the vacuum breaker and install a better check valve.)

[JRTJH]

Anyone who has used a "redneck credit card" (cut-off garden hose) to fill a gas can will attest, once you get the siphon started, it usually is pretty efficient.

Removing the anti-siphon valve from the toilet and converting that plumbing to a "straight through connection" will "convert the backflow system to a "redneck credit card".....

Imagine sitting in a campground, black tank 3/4 full, the DW flushes the toilet and you suddenly start smelling "black tank contents"... You walk around the side of the camper to find "black ooze" dripping out of the tank flush fitting.

All it takes is enough "pressure in the tank" to push fluid "up the hose to the bend" to start the "redneck credit card" action...

As Steve indicated, if there's no pressure check valve (or a malfunctioning valve) at the hose connection on the side of the trailer (or in a compartment on some "upgraded models"), then you're potentially setting yourself up for a "gooey mess"... Even if there is no "credit card action" there is a direct, open line for sewer gas to flow from the "in tank fitting" up the "now open" 1/2" pipe and out the side of the camper, at least until the "in tank fitting" is covered with liquid.

While I don't "fight odors" from my black tank, I certainly don't want an "open port" on the side of my trailer for those gasses to vent with every flush.

[Face Down]

Anyone who has used a "redneck credit card" (cut-off garden hose) to fill a gas can will attest, once you get the siphon started, it usually is pretty efficient.

You left out one important part of the "redneck credit card" and that is you need a good "sucker" to get thing started...and I don't see myself doing any sucking to the hose connections on the side of my camper! :eek:

Good points though from both you and Steve...the more things we can learn the better off we are to make informed decisions. I am perfectly confident in how I have my system setup now and it works for me. With the combo of the elbow that replaced the vacuum breaker being at least 2' above the top part of the tank, the potential outlet (spray nozzle) probably only having a diameter of .05-.1 and my dump/cleaning procedure...for the life of me I do not see how I could run into a problem.

Happy to report that I just got back from a 10 day trip to Myrtle Beach, with 6 people in the camper and plenty of time to fill <ewe> both tanks. I dumped twice, cleaned out twice and there was no goo or odors emitting from the cleanup connections. Wish I could say the same about the guy who camped in front of me for a couple of days. Nothing like trying to enjoy a meal while they camper in front of you has no donut but just the slinky stuck down the hole and his dump valves open the entire time! :(

[JRTJH]

You left out one important part of the "redneck credit card" and that is you need a good "sucker" to get thing started...and I don't see myself doing any sucking to the hose connections on the side of my camper! :eek:

Good points though from both you and Steve...the more things we can learn the better off we are to make informed decisions. I am perfectly confident in how I have my system setup now and it works for me. With the combo of the elbow that replaced the vacuum breaker being at least 2' above the top part of the tank, the potential outlet (spray nozzle) probably only having a diameter of .05-.1 and my dump/cleaning procedure...for the life of me I do not see how I could run into a problem.

Happy to report that I just got back from a 10 day trip to Myrtle Beach, with 6 people in the camper and plenty of time to fill <ewe> both tanks. I dumped twice, cleaned out twice and there was no goo or odors emitting from the cleanup connections. Wish I could say the same about the guy who camped in front of me for a couple of days. Nothing like trying to enjoy a meal while they camper in front of you has no donut but just the slinky stuck down the hole and his dump valves open the entire time! :(

The statement in red isn't completely true. That's "one way" to fill the tube with liquid (in the credit card scenario, the other end wasn't accessible) but all it takes for the action to occur is that the hose be "filled with liquid" and at that point, siphoning will occur. Remember that when the foot pedal on the toilet is pushed, there is a "gush of liquid/solid" dumped into the tank. If that "gush" is sufficient to push waste water "up the 1/2" hose to the bend, then the hose is "full enough" to siphon. Sucking or blowing, either way will start siphoning.... Case in point: Remember the guy that could hold his thumb over the end of the "credit card" and "jerk the gas out of the tank" ??? There wasn't any "sucking involved". He did it by creating a vacuum with his thumb while pulling quickly on the hose, filling it with gas to the high point, at which time the siphoning started and gas flowed..... No mouths ever touched most of our "credit card withdrawls".......

[Javi]

Look guys.. it would take a perfect storm for the system to siphon if you maintain the location of the elbow a minimum of 16" above the top of the black tank (per instructions). It takes roughly .5 psi to raise a column of water 16" and that ain't happening unless the vent out the top of the trailer is completely plugged and you completely filled the tank and the vent pipe. Plus on many of the 5'ers like mine you would have to fill the 3" drop pipe all the way to the toilet as well..


And the hose bib would have to be open to the atmosphere...



Well that or you would have to suck really, really, really hard on the end of the hose... :D

[ChuckS]

Even though our Alpine has a tank washout hookup I prefer to use my clear adapter fitting that goes on main outlet dump and reverse wash this way. I can see when tanks are clean and J am not worried about a bad vacuum breaker valve.


Sent from my iPhone using Tapatalk

[hankaye]

ChuckS, Howdy;

Even though our Alpine has a tank washout hookup I prefer to use my clear adapter fitting that goes on main outlet dump and reverse wash this way. I can see when tanks are clean and J am not worried about a bad vacuum breaker valve.


Sent from my iPhone using Tapatalk

If there is a "straight shot" into your tank from the hose connection on
your clear adapter that would work well. However, if there is an elbow
between the clear adapter and the tank or the plumbing enters from the
side then you are only cleaning that section of pipe run. The elbow or the
opposite side of the tank will stop any pressurized water from traveling
any further, other than a few inches or will puddle at the end of the tank.
Next time you dump, use your method, then give the clean-out a shot to
see what, if any difference there may be.

hankaye

Sent from my lap-top using hunt-n-peck

[SmittysRV]

ChuckS, Howdy;



If there is a "straight shot" into your tank from the hose connection on
your clear adapter that would work well. However, if there is an elbow
between the clear adapter and the tank or the plumbing enters from the
side then you are only cleaning that section of pipe run. The elbow or the
opposite side of the tank will stop any pressurized water from traveling
any further, other than a few inches or will puddle at the end of the tank.
Next time you dump, use your method, then give the clean-out a shot to
see what, if any difference there may be.

hankaye

Sent from my lap-top using hunt-n-peck

My bet is there will be some "stuff" that you will see flowing threw the clear adaptor when the "sani flush" is used even after you flush with you method...

I usually pull the black tank first, let it stop flowing, close it, turn on sani flush and time it for 4 minutes, during this time I pull secondary grey (Kitchen sink island), after 4 minutes has passed I close secondary grey and pull black tank again. Keep it open until flow slows to where it is just the water going in from the sani flush. I close the black one more time for another 4 minutes. Ill go back to the secondary grey if it wasn't completely empty the first pull. After another 4 minute sani flush I once again open up the black and drain till clear then shut off sani flush. Lastly I pull the primary grey and drain till empty. Done deal!!! Seems to work well and my gauges always go to empty. Hope this helps, good luck!

[JRTJH]

Let's do a little comparison (just for grins)....

Drive your tow vehicle, covered with wet mud to a car wash, fill a bucket with soap and water and throw it at the side of your muddy truck. Let it "drain until it stops dripping" and look at the results... Still muddy? Probably.

So now, let's put a few quarters in the car wash. Use the soap selection (low pressure) and spray some soapy water on that same muddy side of the truck. Let it sit until it stops dripping. Still muddy? Probably.

Now, let's use the high pressure spray to try to knock the mud off the truck. Spray it until the "quarters time out" and let it stop dripping. Now, use a clean wash cloth and wipe the side of the truck. Is the wash cloth clean, or does it have some of the remaining mud on it? Let the truck sit until it stops dripping and then drive it to a "sunny spot" and look at the results. Is the truck clean? or is there a "swipe mark" where you wiped it with the wash cloth?

Now, to explain my point: Using low pressure water (filling the tank with clear water), even soap and water with "some pressure" (using the tank rinse system and adding some soapy solution), even using the "high pressure wand" (down the toilet rotary "tank cleaner") most likely isn't going to "clean your tank" completely.....

The best most of us can expect, especially when using 40 PSI regulated water at a campground, to put 4 minutes of water (4 min x 3 gallons per minute) or about 12 gallons of water under low pressure into the tank, won't "clean" the tank. Filling it "FULL" and dumping repeatedly still won't get "all the dirty parts" out of your tank.

Once a black tank has been used, there's going to be remnants of toilet paper, solid waste and remaining liquids that hang up on the probes, get stuck on the rough sawn edges of the vent stack and the toilet dump stack as well as other "not fully level and completely drained" areas of the tank. Not to mention the "soiled residue that adheres to the inner tank walls.... (think of the mud stuck to the sides of your truck)....

My point is that you can't get "inside the tank" to scrub it and mechanically clean all the residue from the tank walls.....

So, consider that it'll never be clean, dump, rinse, add your chemicals/soapy home solutions to the tank (hopefully to help dissolve the "goo" that sticks to the walls and probes) and remind yourself that the first time you use the toilet, it'll be "just like it was before you started cleaning"....... After all, it's made of "black plastic" for a reason.... Most likely, so you can't see what's left after your diligent efforts to remove everything......

[Face Down]

The cleanest the tank will ever be is before it is ever used. In tank sprayer is the best way to "somewhat" get a tank clean...anything else is just a waste of time and money.

https://www.youtube.com/watch?v=dfTd0Slt_cU

[hankaye]

Howdy All;

Now ifin y'all really want a clean tank here's yer fella
http://www.allprowaterflow.com/

John, he does the high pressure wash and has a video camera so
you can inspect it when he's done...

hankaye

[JRTJH]

Howdy All;

Now ifin y'all really want a clean tank here's yer fella
http://www.allprowaterflow.com/

John, he does the high pressure wash and has a video camera so
you can inspect it when he's done...

hankaye

I've seen that website before. He has a "compelling service" for someone who doesn't fully understand the function of a black tank or who is "obsessed with a clean "black tank"....

I'd have to ask: When he's done and the camera "shows the tank is clean" will he store his "tater salad" in it? If not, well, I think I made my point: It's a "poo tank" high pressure clean or not, it's always gonna be a "poo tank" If you get the "big chunks" out and rinse it, it's "clean enough to use as a "poo tank" but no matter what you do, it's still not going to be "tater salad clean"...... :cool:

[SmittysRV]

Let's do a little comparison (just for grins)....

Drive your tow vehicle, covered with wet mud to a car wash, fill a bucket with soap and water and throw it at the side of your muddy truck. Let it "drain until it stops dripping" and look at the results... Still muddy? Probably.

So now, let's put a few quarters in the car wash. Use the soap selection (low pressure) and spray some soapy water on that same muddy side of the truck. Let it sit until it stops dripping. Still muddy? Probably.

Now, let's use the high pressure spray to try to knock the mud off the truck. Spray it until the "quarters time out" and let it stop dripping. Now, use a clean wash cloth and wipe the side of the truck. Is the wash cloth clean, or does it have some of the remaining mud on it? Let the truck sit until it stops dripping and then drive it to a "sunny spot" and look at the results. Is the truck clean? or is there a "swipe mark" where you wiped it with the wash cloth?

Now, to explain my point: Using low pressure water (filling the tank with clear water), even soap and water with "some pressure" (using the tank rinse system and adding some soapy solution), even using the "high pressure wand" (down the toilet rotary "tank cleaner") most likely isn't going to "clean your tank" completely.....

The best most of us can expect, especially when using 40 PSI regulated water at a campground, to put 4 minutes of water (4 min x 3 gallons per minute) or about 12 gallons of water under low pressure into the tank, won't "clean" the tank. Filling it "FULL" and dumping repeatedly still won't get "all the dirty parts" out of your tank.

Once a black tank has been used, there's going to be remnants of toilet paper, solid waste and remaining liquids that hang up on the probes, get stuck on the rough sawn edges of the vent stack and the toilet dump stack as well as other "not fully level and completely drained" areas of the tank. Not to mention the "soiled residue that adheres to the inner tank walls.... (think of the mud stuck to the sides of your truck)....

My point is that you can't get "inside the tank" to scrub it and mechanically clean all the residue from the tank walls.....

So, consider that it'll never be clean, dump, rinse, add your chemicals/soapy home solutions to the tank (hopefully to help dissolve the "goo" that sticks to the walls and probes) and remind yourself that the first time you use the toilet, it'll be "just like it was before you started cleaning"....... After all, it's made of "black plastic" for a reason.... Most likely, so you can't see what's left after your diligent efforts to remove everything......

I've seen that website before. He has a "compelling service" for someone who doesn't fully understand the function of a black tank or who is "obsessed with a clean "black tank"....

I'd have to ask: When he's done and the camera "shows the tank is clean" will he store his "tater salad" in it? If not, well, I think I made my point: It's a "poo tank" high pressure clean or not, it's always gonna be a "poo tank" If you get the "big chunks" out and rinse it, it's "clean enough to use as a "poo tank" but no matter what you do, it's still not going to be "tater salad clean"...... :cool:

Not sure any of us are trying to get out Black "poo tanks" white glove, "tater salad" clean. My post above was just an option that I use and works for me. It gets the big chunks out, at least most of them....:eek: and if it is only 3 gallons per minute (not sure where to look that one up at) I will definitely increase the flush time!!! If 3 gallons per minute is obtained from a water hose wide open at 40psi I am sure that the little nozzles inside the black tank change that flow rate drastically, in the negative direction. But then again I would hate to get in trouble by the water Police during this big drought in Cali...

[JRTJH]

Here's one calculator that give the options for different size hoses and different water pressures: http://irrigation.wsu.edu/Content/Calculators/Residential/Garden-Hose-Flow.php

If you consider a half inch hose at 40 PSI, you'd get about a 6 GPM flow rate. Run that through the "spin head" in the tank and it will reduce the volume by about 50% (around 3 GPM).

This thread has seemed to "lose perspective" on emptying/flushing the black tank and turned the corner on "cleaning the black tank". My point, at least from my perspective, is this:

1. No matter how much you try, it's still going to be a "dirty tank".
2. None of us (I hope) are going to use the "cleaned tank" as a sanitary vessel, so why focus wasted effort on trying to make it "clean".
3. The first "flush" after cleaning will reintroduce all the "dirty stuff" (but not as concentrated) and essentially make the "clean tank" dirty all over again.
4. No matter how much "scrubbing, cleaning and flushing" one does, it's still going to be a "dirty tank" complete with the smells and "aura" associated with a "dirty tank". (If you don't believe it smells after cleaning, get a little closer, close your lips and breathe in deeply.)
5. You can't "clean it" and "make it anything else".
6. Proper flushing, rinsing and use are the best way to care for any black tank. Keep the contents liquid, don't let the tank dry out, use chemicals/home concoctions for odor control and don't focus on "cleaning" (an impossible task) as much as proper emptying/flushing.

So, if anyone has another "perspective" about the black tank, I suppose you're free to disagree with the above philosophy of just what is a "poo container".....

For me, when using the RV, I pull the handle, let the brown stuff escape, close the handle and add about 4 or 5 gallons of water through the toilet foot pedal. There's no need to spend time or waste water "flushing and cleaning" because it's going to "fill with the same stuff" with the first use. On the last emptying at the end of the season (or if prolonged storage is anticipated) flush the tank (to empty as much solid residue as possible) and head home. For me (others may not agree) obsessing about cleaning the black tank and getting "everything out with every flush" is wasted effort. It's just going to fill up again with the same stuff so a 2 or 3 or 10% residual just won't make the tater salad taste any different.

[SteveC7010]

The cleanest the tank will ever be is before it is ever used. In tank sprayer is the best way to "somewhat" get a tank clean...anything else is just a waste of time and money.

https://www.youtube.com/watch?v=dfTd0Slt_cU
I took the time to watch this 25 minute video, and there's clear and compelling argument to use the in-tank spray systems based on the experiments performed in the film.

Clear points proven:

1. The in-tank spray systems are the only way to clean the walls of your tank. Refilling the tank from the dump end does not really remove any significant amount of debris.

2. The in-tank spray systems do the best job of clearing out a good deal of whats on the floor of the tank. You may have to close the valve and let the spray run for a couple of minutes and then dump again to accomplish this very acceptable level of clean.

3. A clear fitting at the dump fitting doesn't give a true picture of what's been removed from the tank unless you use the in-tank spray cleaner.

One point I would argue is that the Sewer Solution is an effective tank cleaning device. It's not. Its primary function is as a water flow driven pump to dump your tanks in situations where the standard 3" dump hoses can not be used. I had two of them and used them at my last home. They both broke over time and I did not replace them. (#2 was a warranty replacement and did not hold up any better than the original.) They do work as advertised, but use a lot of water. We were on a well there, and had volume issues so the running the Sewer Solution was not ideal. The spray clean out capabilities of the Sewer Solution are effective only in the piping near the dump port. Like other similar devices, it doesn't put any useful spray up in the tank. I discounted it as a cleaning device then and even more so now.

The real purpose of cleaning the tank here is to keep as much debris off the sensors as possible and to prevent any chance of a DBP (dreaded black pyramid.) When we had the Sunline, the black tank was only about 7" tall and did not have a built-in spray system. But the toilet was only inches above the tank so I could use one of the spray wands very effectively. With the Cougar, the tank is taller, but it has sprayer systems. After I dump and rinse with the in-tank sprayer, I look down the toilet with a flashlight. All I usually see is water and the tank floor. If there's no remaining visible debris and the water runs clear at the dump fitting, I am more than satisfied.

"Tater salad" stays in the fridge!

Now, I'm really beginning to wonder why there's no spray system in the gray tanks, especially the one that serves the galley. The buildup of food and grease on the walls and floor must be really ugly. I don't have the time to install an in-tank spray system right now, but it has been placed on my list of mods for next season. I am going to take a closer look at cleaning agents in the next couple of weeks.

[hankaye]

Howdy All;

As I dwell in mine on a full time basis my object it to keep it
as clean as possible. I dump mine regularly on Saturdays. If
it ain't sayin' it's full I fill it with the foot valve. Then go about
my routine. 3 1/2 years (almost), and no pyramids (touch wood).
2 1/2 years in the old TT and no pyramids either... (had a flush
wand for that one).
'tater salad should be eat'n off'n a paper plate and should have
some drippins from the ribs or some other slow cooked critter to
enhance the flavors of both... :D

hankaye

[Desert185]

OCD with regard to black tank cleaning is a frustrating and futile effort. Just use the black tank flush system on an every two or three time basis and don't put corn in your tater salad. OCD that tater salad in another manner that will quell your impulsive culinary attempts and be of less concern when removing solids from your black tank. :D

[SmittysRV]

I took the time to watch this 25 minute video, and there's clear and compelling argument to use the in-tank spray systems based on the experiments performed in the film.

Clear points proven:

1. The in-tank spray systems are the only way to clean the walls of your tank. Refilling the tank from the dump end does not really remove any significant amount of debris.

2. The in-tank spray systems do the best job of clearing out a good deal of whats on the floor of the tank. You may have to close the valve and let the spray run for a couple of minutes and then dump again to accomplish this very acceptable level of clean.

3. A clear fitting at the dump fitting doesn't give a true picture of what's been removed from the tank unless you use the in-tank spray cleaner.

One point I would argue is that the Sewer Solution is an effective tank cleaning device. It's not. Its primary function is as a water flow driven pump to dump your tanks in situations where the standard 3" dump hoses can not be used. I had two of them and used them at my last home. They both broke over time and I did not replace them. (#2 was a warranty replacement and did not hold up any better than the original.) They do work as advertised, but use a lot of water. We were on a well there, and had volume issues so the running the Sewer Solution was not ideal. The spray clean out capabilities of the Sewer Solution are effective only in the piping near the dump port. Like other similar devices, it doesn't put any useful spray up in the tank. I discounted it as a cleaning device then and even more so now.

The real purpose of cleaning the tank here is to keep as much debris off the sensors as possible and to prevent any chance of a DBP (dreaded black pyramid.) When we had the Sunline, the black tank was only about 7" tall and did not have a built-in spray system. But the toilet was only inches above the tank so I could use one of the spray wands very effectively. With the Cougar, the tank is taller, but it has sprayer systems. After I dump and rinse with the in-tank sprayer, I look down the toilet with a flashlight. All I usually see is water and the tank floor. If there's no remaining visible debris and the water runs clear at the dump fitting, I am more than satisfied.

"Tater salad" stays in the fridge!

Now, I'm really beginning to wonder why there's no spray system in the gray tanks, especially the one that serves the galley. The buildup of food and grease on the walls and floor must be really ugly. I don't have the time to install an in-tank spray system right now, but it has been placed on my list of mods for next season. I am going to take a closer look at cleaning agents in the next couple of weeks.

Im with ya on the Grey tank!!! I have that second grey (Galley Island) tank and it smells worse than the black tank when dumping.... I have used bleach in there in the past abd it seems to help but I think Im with you and will look more into adding a Sani FLush set up like our Blank tank has.