Word of advise. What you start with will not be what you finally end up with. (WHAT?
) really.
For example: You may purchase sewer hoses, looking for the best your available money can buy. But a year from now, they will fail. They will get pin-holes, leads, connections break.... any number of things can happen that will force you to buy another new one. The second purchase will be a bit wiser, again depending upon the best your "available" money can buy.
We've been through, probably 50 sewer hoses over 30 years of camping. We've had 4 different surge protectors/EMS devices.
We've tried different water filters over the years, and finally, we are not using any now. Never had a problem with water anywhere. It took a while to realize we didn't need them at all.
Even the electric cords you purchase for your camper, will eventually fail, crack, break, get run over by a lawn mower, something will happen that will cause you to have to purchase new again. When that happens, you'll be rethinking the next purchase.
In a nut shell, don't over think it. What works well for one person, may not work well for someone else. Use your best guess judgment ... based on what you can afford, and be prepared in a year to replace everything. (It will happen).
The second purchase, is always more wise and more informed than your first.
When you sell your current camper and get a new one, you'll be doing this all over again.
Black water chemicals. Oh we've tried different kinds; liquids, little plastic baggies you drop "down there". We tried the orange ones, the blue ones, the green liquid stuff. And we found out, the best method was just water and bit of Dawn Dishwashing liquid (Look up Geo Method). So, this changed over the years too.