Determining tank capacities.

[mwemaxxowner]

I'm starting to look at portable dump tanks for stays where there is no sewer connection on site. I looked up the specs on my camper on the Keystone website, and it listed me as having 24 gallons black tank capacity and 60 gallons of grey water.

What in curious about, is whether it's reasonable to assume that that is a 50/50 split with my galley tank and my bathroom grey water? Is there a placard I may find somewhere that tells me? I want a large enough portable tank so that any time I want to dump a full tank I can dump the whole thing at once.

[chuckster57]

The 60 gal of gray would include both gray tanks. So it would appear that all 3 tanks are about 30 gallons each. A 30 gallon tote would take all the contents of one tank.

[mwemaxxowner]

I know it includes both tanks, which was the reason for my question. Do we know it is a 30/30 split, or is that just an assumption? Not, 35/25, etc. I don't want it to get full then have 5 more gallons waiting for me to unhook the hose. (Yikes!)

[chuckster57]

You can do one of two things to check. Pour 5 gals at a time from a bucket, or fill the tanks and drain into a 5 gallon bucket. You’ll know the exact amount one way or the other.

We have had customers fill the tanks and measure with a bucket during walkthrough.

[mwemaxxowner]

I was just hoping there was a way to look ut up, or if perhaps somebody knew that Keystone always makes them both the same size or something. Or of maybe there was a placard somewhere that lists that information that I haven't found.

5 gallons at a time sounds like a pretty darn good idea though.

[uavpilotmk]

We have a 36 gallon dump tank and it’s about one man can handle by himself. It can sometimes be a chore getting the tank to your tow vehicle to bring it to the dump station to empty. Think about it. 36 gallons x 8lbs per gallon minimum = 288 lbs.

[mwemaxxowner]

I would like to think all I need is 30 gallons. I spend a lot of time intentionally dragging heavy things around for fun. Lol. I call it "training".

Mostly, the smaller I get the cheaper it will be, so no need for several reasons to get one larger than I need. But at the same time I don't want to limit my dump capacity and have to dump more often.

[chuckster57]

I have yet to see any placard or label that lists tank capacities for a specific unit. The tank itself may have capacity molded into the label but that means opening up the underbelly. And of course when you look up the specs on line there is a disclaimer at the bottom of the page:

“Subject to change without notice”.

[mwemaxxowner]

Sounds like a bucket it is! [emoji2361]

[mwemaxxowner]

This is all I've been able to find, which was better than nothing. I gave considered contacting Keystone, but when I did so for assistance with keys they just referred me to a dealership. 22936

[uavpilotmk]

I would like to think all I need is 30 gallons. I spend a lot of time intentionally dragging heavy things around for fun. Lol. I call it "training".

Mostly, the smaller I get the cheaper it will be, so no need for several reasons to get one larger than I need. But at the same time I don't want to limit my dump capacity and have to dump more often.



I think you just answered your own question. LOL.

[mwemaxxowner]

I think you just answered your own question. LOL.I mean, that's assuming neither of my grey tanks are over 30 gallons. Lol

[JRTJH]

Consider that gray tanks, unlike black tanks, can be partially emptied without concern for "fouling the tank slide valve".... In other words, there's nothing in a gray tank contents that would get caught in the valve and make it stop sealing/working to close the tank. Think toilet paper, etc that, if the slide valve is pushed closed while that "stuff" is passing through the valve and is pushed into the rubber seal cavity, you've got a PROBLEM !!!

That won't happen with gray tank contents. So, if you want, you can empty a 45 gallon gray tank with a 10 gallon "blue tank"... just open the slide valve, fill the portable container, and when it's full, close the slide valve, go empty the portable tank, return and repeat as necessary....

Your comments: "Mostly, the smaller I get the cheaper it will be, so no need for several reasons to get one larger than I need. But at the same time I don't want to limit my dump capacity and have to dump more often."

What you're saying, from the way I read it is that you don't want to buy a bigger tank but you also don't want to make multiple trips to dump the smaller tank.... Looks like you're going to have to choose one or the other, or, probably a better choice, get the largest tank that fits your physical abilitiy to "manhandle" and also fits the space you have to store it for travel. It doesn't do much good to have a "one trip tank" if it won't fit in a space so you can take it with you and it doesn't do much good to buy an "affordable" 3 gallon portable tank" (when a 5 gallon bucket would do a better job).

I know the above goes to both the "too big" and the "too small" extremes. Each RV'er needs to compromise to fit both their needs and their ability to move/transport/store their choice of portable tanks.... That's why the come in multiple styles and sizes.

Rather than just focus on "how big is my "gray tank", you might also want to consider, "Where will I store this tank when I'm travelling and how easily will I be able to pull it around the campsite and transport it to the dump station?"

[mwemaxxowner]

You're exactly right. I don't want to spend substantially more than I NEED to on a portable tank, but I don't want to essentially limit my grey tank capacity because I can't dump all of it at once. Thereby reducing the time I can go between dumps. I'm also not sure what sort of mess I could encounter if I fail to close the tank valve in time once the portable tank is full. Just for grey water though I know that wouldn't be a huge problem if I spill the contents of the sewer hose.

I don't think I need to choose one or the other, I like the suggestion to just use a 5 gallon bucket and measure it myself. Seems a little nutty to have to resort to that just to know the sizes of the tanks installed on a camper, but hey what else can ya do!? [emoji4]

I would say that I'll just do that using the tub as my drain. Should be the easiest way.

5 or 10 more gallons isn't going to make it break my ability to drag the tank to my truck to pull to the dump station, and the extra effort is well worth extending the time between dumping for me. Same goes for storing the tank.

[travelin texans]

This is all I've been able to find, which was better than nothing. I gave considered contacting Keystone, but when I did so for assistance with keys they just referred me to a dealership. 22936

To add to the confusion that list states "LPG-40", that doesn't mean you have 40 gallons, but rather 2-20lb bottles = 10 gallons or 1-40lb = 9+ gallons.
From experience with my "little blue buddy" make yourself a 3" hose just long enough the connect to the portable tank with no sag, that will save a lot of mess. Believe me it goes into that tank A LOT faster than you can stop it.

[mwemaxxowner]

I assumed what that meant was 40 lbs, but it's cool to know what that equates to in gallons.

It actually had two 30lb tanks when I bought it. They were too old to refill, so I have two 20 lb tanks on it now. I use very little propane.

[Roscommon48]

get a 'blue boy' and move on.

as for time before you dump, it will greatly depend on you. One person, and not many showers it could be weeks. black water will be weeks too.

[mwemaxxowner]

I know it depends on how quickly we go through water, but if I'm leaving 5 or 10 gallons on the table, IMO that's a lot to sacrifice. Depending on the trip even one more day of use could be a big deal.

My question has been answered: no there is not apparently published information available on the individual grey tank capacities. I will measure myself, and know what size tank I need to buy. Thank you all.

[BadmanRick]

I have a 2011 bullet Premier 19fbpr it has a 30 gal gray and a 30 gal black. I have a barker 32 gal 4 wheelers tote tank. I normally run the gray open and when tank gets full I dump it. When my black tank gets full I empty it into the tote tank and empty it. Then use the gray to clean the blue tote tank.

[Firegod]

I am having the same issue with a brand new cougar. It's BS that somebody from Keystone can't tell us what size the tanks are that THEY installed.

All the dealer can stay is that "I think" they are equal size.

[chuckster57]

I am having the same issue with a brand new cougar. It's BS that somebody from Keystone can't tell us what size the tanks are that THEY installed.

All the dealer can stay is that "I think" they are equal size.

When you call Keystone, the person on the phone at the other end isn't going to have ALL the specs on ALL the trailers Keystone carries and as I stated before, specs are subject to change at anytime.

[RickReichert]

I bought a cheap plastic digital water meter that hooks onto a garden hose. Filled each tank separately. Easy!

[RayT]

I'm not the original owner of my 2012 Montana and didn't get all the original paperwork when I purchased it. I did find specs online that claimed my total gray tank capacity is 93 gallons.

I had also contacted Keystone to get other build info and at the time they told me the 93 gal was split evenly between the two tanks.

I recently had part of the chloroplast pulled and was able to get my cell phone close enough to the two tanks to take photos of the labels on the tanks with the manufacturer name and model number (Ameri-Kart HT541 & HT542). An internet search provided the correct info, both tanks are 40 gal, for a total capacity of only 80 gallons!

So much for truth in marketing

[travelin texans]

I bought a cheap plastic digital water meter that hooks onto a garden hose. Filled each tank separately. Easy!

Ok! Now that you know tank sizes does it really make a difference in how you use them? The sensors are not calibrated in gallons & are mostly useless! Will you use the same cheap digital meter to measure input from each sink & the toilet? Unless you do nothing has changed, when they're full they're full. Also because it holds xx gallons doesn't mean you'll ever fill to or dump xx gallons, once liquid has been added you'll never drain it all again.

[Nitehawk]

I like this... just something g else to add to my " buckets list" of things to do..

[dcount]

I recently did a little test on all three of my tanks, they are supposed to be 30 gallons each, 1 black and 2 gray. I was checking how close the tank level lights were to reality. Used a 5 gallon bucket, the lights were surprisingly accurate, and all tanks checked out to approximately 30 gallons eack. But we still get some weird readings when camping.
I would think from a manufacturing/assembly perspective, you would want to minimize SKU's and stock locations, so using the same 30 gallon tank in as many applications as possible would make the most sense.

[Ppk123]

Get the 36 gallon you won’t be unhappy, but forewarned when you have 300 pounds in the tank the wheels are only rated for about 75 each.I had one that I use six or seven times and the wheel broke. Put on wheels that would hold 175 pounds each. But I had to fix the axle the It was 5/8 shaft machine to a half inch axle. The bigger wheels are 5/8 shaft .

[mwemaxxowner]

Ok! Now that you know tank sizes does it really make a difference in how you use them? The sensors are not calibrated in gallons & are mostly useless! Will you use the same cheap digital meter to measure input from each sink & the toilet? Unless you do nothing has changed, when they're full they're full. Also because it holds xx gallons doesn't mean you'll ever fill to or dump xx gallons, once liquid has been added you'll never drain it all again.It's useful if you're searching for a portable dump tank. Otherwise, sure it doesn't matter. I don't see a need to spend more money than I need on a tank, but at the same time I want to make sure I can dump the entire tank while I'm at it.

[mwemaxxowner]

When you call Keystone, the person on the phone at the other end isn't going to have ALL the specs on ALL the trailers Keystone carries and as I stated before, specs are subject to change at anytime.I know that wasn't directed towards me, but I definitely understand that. It seems to me this information should be published somewhere though. It doesn't seem that it is.

[Yankee Clipper]

I may have been lied to but when I called Keystones for this info they asked for my S/N and then told me the three sizes.

[chuckster57]

I may have been lied to but when I called Keystones for this info they asked for my S/N and then told me the three sizes.


With a VIN and the right person, they may be able to access the “build sheet”. That sheet will have model and serial numbers, it may also include tanks.

I do know when we submit a warranty claim, we have to include model &serial number.

[sealyin]

Don't believe the printed material. Measure it yourself. The specs for our 2017 Cougar Half ton series 26RBIWE say 38 gallon black and it only holds 30 gallons when I poured in 5 gallon buckets as suggested above. Measured it twice to make sure I did not miscount the buckets but got 30 gallons both times.

[JRTJH]

Don't believe the printed material. Measure it yourself. The specs for our 2017 Cougar Half ton series 26RBIWE say 38 gallon black and it only holds 30 gallons when I poured in 5 gallon buckets as suggested above. Measured it twice to make sure I did not miscount the buckets but got 30 gallons both times.

If you look at the construction shape of most holding tanks, they are "long, flat, skinny tanks with the sensors mounted in the end. A "slightly off level trailer" (side to side) may well displace 1/3 or 1/2 of the "liquid at that end of the tank" and make you think your tank is half full when it's full or make you think it's full when it's half full.

In addition to that, if you pour 5 gallon buckets into a tank that's in a trailer that is "leaning toward the end without sensors" you may find that it has an "air gap" at the end and won't hold the entire "38 gallons" but only holds 31 gallons (example only) and the other 7 gallons are "consumed by air that can't be displaced by water from your bucket"... Then there's the possibility that the tank is "squished in the middle" by a beam under it, a lateral brace that doesn't let the tank fully expand or even a vent stack that's inserted too deeply into the tank, preventing it from expelling excess air as the tank fills with water....

There's significantly more to "my 38 gallon tank won't hold 38 gallons" than just an "incorrect tank must have been installed"

[sourdough]

^^^^Which goes back to travelintexans post about "why obsess" about this stuff. Black/gray tanks come in all kinds of sizes. The manufacturer may or may not tell you exactly what it is due to any number of "issues". Trying to assess the "exact" capacity to then buy some "accessory" that exactly fits is just....wishing. It is what it is....put the tote down, listen to it, close the valve, tank empty or not if it sounds full. Have to make 2 trips? Oh well, that's RVing.

Like wiring, outlets and anything else, you have to learn to deal with it unless you just want to tear the RV apart and "trace" wiring, "affirm" tank capacities, "insure" water line/plumbing routing (assure construction parameters); just for grins. At the same time you could pull all the interior/exterior walls off to ascertain exact locations of the wall studs, floor joists etc. I choose to learn it, deal with it and go have fun.

[mwemaxxowner]

^^^^Which goes back to travelintexans post about "why obsess" about this stuff. Black/gray tanks come in all kinds of sizes. The manufacturer may or may not tell you exactly what it is due to any number of "issues". Trying to assess the "exact" capacity to then buy some "accessory" that exactly fits is just....wishing. It is what it is....put the tote down, listen to it, close the valve, tank empty or not if it sounds full. Have to make 2 trips? Oh well, that's RVing.



Like wiring, outlets and anything else, you have to learn to deal with it unless you just want to tear the RV apart and "trace" wiring, "affirm" tank capacities, "insure" water line/plumbing routing (assure construction parameters); just for grins. At the same time you could pull all the interior/exterior walls off to ascertain exact locations of the wall studs, floor joists etc. I choose to learn it, deal with it and go have fun.With all due respect, I'm not obsessing over it. I inquired about where I may find information about the capacities of my tanks. Then I was informed there pretty much isn't any, I'll have to measure it, which is good enough to me. Then conversation and posts continued and we continue to participate.

If I wish to know the size of my tank, so that I can maximize a dump into a portable tank, I'm welcome to and I don't think that is an unreasonable wish. On a weekend trip, that could well mean the difference between using the portable tank twice and then having just a couple gallons left after the last day or two to dump on the way out, and only dumping into the portable tank once. You get the idea.

[sourdough]

The term "obsess" was used as a quote from a previous post. How anyone wants to approach anything related to their personal use/experience with their RV is their choice of course.

In this situation I was trying to point out that each RV is built independently of the next one; literally each one is a "one off" and unique unto itself. Trying to find the exact details of a particular unit is a waste of time generally so it depends on what the owner can determine, first hand, about his particular unit. In your case, I completely understand the reason you want to know and it sounds like you have come to a plan on how you want to approach it as best I can tell.

My comments weren't directed at you particularly but more a general statement of how these things are put together and the extent to which one may, or may not, want to go to figure out exactly what it is that they own - and how much trouble it would be to learn ??.

As far as dumping the black tank into a tote, I've never owned a tote BUT I did spend a lot of time helping my best friend use his. I said then I never would and never have; sort of llke a porta potty - too much trouble. Also, 40 gals. of "stuff" weighs well in excess of 300 lbs. Seems way too much to try to navigate by hand around a rough, hilly campsite location. I did look up one that might be a little more handy than what I originally envisioned (handling by hand). It appears to stay flat on the ground and has a loop so that you could attach it to a vehicle/ATV for transport to a dump site;

https://www.walmart.com/ip/Barker-42-Gallon-4-Wheeler-Tote-Along-30844-RV-Portable-Waste-Tank/42496703?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227034519497&wl0=&wl1=g&wl2=c&wl3=92141241648&wl4=pla-128646940608&wl5=9028507&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=42496703&veh=sem&gclid=EAIaIQobChMItsXa_sra4wIVBI9bCh1N5gR9EAQYASAB EgLev_D_BwE

Good luck on your choice and hope you find a way to "conveniently" handle the "stuff". :D

[mwemaxxowner]

Ideally we're only going to stay short trips at places that don't have on site sewer. Also, ideally when I DO have to use a portable tank, I'll be able to have very little, if none at all distance to get it to the truck and let the truck do the heavy lifting from the camp site to the dump station.

I'm sure we're also all well aware that ideal doesn't always happen, but IF I find myself in strange situations where I would have a long way to drag it by hand, I can always choose those times to not fill it completely. The state park we stayed at recently I could have dumped into the tank while attached to the truck, then driven a hundred yards to the dump station. Never having to move it at all by hand and also not having to drive it behind the truck all that far. That particular place is one we hope to frequent often .

[Campbuddy]

We recently got a 25 gallon tote that has 6” wheels. The first trip we took it on we were over a mile to the dump and there were speed bumps. The instructions for the tote said not to go faster than a walking pace. The larger the wheels you get, the faster you can go.

[mwemaxxowner]

I really wasn't expecting to get excited while unboxing my poo tank...but I did. Lol.

I still haven't measured my tanks (the camper is set up far enough from the nearest water source that the hose we have doesn't reach all that close), but I bet 32 gallons is a good bet for being large enough. If I'm 5 or so gallons shy I can always use a 5 gallon bucket or even two with a lid on them if it was necessary.

I found a few this size cheaper, but they had horrible reviews. It came down to this one, and the Camco Rhino 36 gallon. I think it would have been a good choice too, gets good reviews, no complaints of wheel or axle failure or whatnot, etc. The deciding factor for me was 4 wheels, and not having to support the front when I do need to roll it by hand. I would imagine distributing the weight amongst 4 wheels instead of two will help it live a longer life.

I have steel wheels, pneumatic tires, and greasable bearings. It seemed that most complaints in the reviews on other models were wheel failures, many melting in the center due to no bearings.

It has a level sensor, of sorts. It's also lower profile than the Camco Rhino that I was looking at.

I think it was 217 shipped or something like that. We're camping a week from tomorrow. I'm sure we won't fill our tanks, but I may use this thing on the last day anyway just to get some experience with it. 2313623137231382313923140