New Waste Water Tank

[Glennman]

I'm almost finished installing my Class A Customs 125 gallon black/gray waste water tank. It is only advertised as either fresh or gray for understandable reasons. However, it is what it is. I installed the rubber exit port on the side that will be the drain. That rubber adapter filling is impossible to install at the very bottom since it has a flange, so it ends up about 3/4" from the bottom. I was thinking about pouring some 2 part epoxy in that end of the tank to bring the bottom up to the bottom edge of the flange, but that does seem like a lot of trouble. I see a lot of tanks adapted for similar applications like mine, so I am wondering if anyone has a problem with solids and toilet paper accumulating there. If I leave the valve shut all the time and only drain it when there is sufficient volume, does accumulation occur? Seems like things are pretty broken up by then.

[richard5933]

I have a single waste tank - combined gray & black. The discharge line is connected with a bronze flange. Even with the bottom of the flange trimmed down, there is still about 3/4" below the discharge opening.

So far I've never had a problem with this. At the end of the season I park on a sloped portion of the driveway to get out all but a tiny amount from the tank, and then the few gallons of pink antifreeze which go in during the winterizing is enough to keep it from causing any freeze damage.

[chessie4905]

Not a problem. Don't  let it dry until after rinsed out at end of season, or flush and add some rv antifreeze. Hopefully it's  vented through roof.

[Glennman]

Not a problem. Don't  let it dry until after rinsed out at end of season, or flush and add some rv antifreeze. Hopefully it's  vented through roof.

With what both you and Richard5933 said, I think I'm doing ok. I'm not too sure of my 2-part epoxy mix and pouring it in the bottom to try to raise the level of the bottom up to the outlet. It might work, but getting anything to stick to the tank plastic is not a sure thing. Thanks.

[richard5933]

I see no need to add a complication to the tank like a false bottom. Seems like a recipe for disastrous problems when some liquid gets under it (and it will eventually) since it won't be possible to remove the epoxy.

[David Anderson]

I'm with Richard on this.  Don't add anything.  I don't empty my tanks unless I will use the coach and add more waste.  I always keep waste in it.  (I don't have to worry about freezing) The remainder on the bottom would dry like cement without water.  I keep the valves closed and only dump when full.   

Since you are combined you may want to have a port to stick a nozzle in and spray around maybe once a year or every 2 years. 

For an occasional thorough cleaning jack up one side of the coach and spray through the port to really clean it. 

Keep it simple.  This is a nasty requirement of the rv world to deal with. 

David

[Dave5Cs]

I have a 3 inch sewer cap on the top outside corner. After we dump I just open it up and use a sprayer like Dave said and spray it out but also put a few gallons of clean water in it in case there is anything left so it won't dry and stick.