Black tank not draining completely. 2021 Imagine 2600RB

[fish8it]

I have a 2021 Imagine 2600RB and the black tank does not drain completely. There is also one dot on the black tank display. I have confirmed that the tank is not empty by looking down the toilet and taking a stick to check. Seems there is about one inch of fluid still in the tank. I use quality tank fluids and use the black tank flush until clear water comes out. I fill it with water about 3/4 full when flushing it out. I do this about three times. Both Lazydays RV in Tucson and Grand Design say having leftover water in the tank is normal. I have never owned a RV where the tank would not empty completely. I am looking for others that might have the same issue. If you own a like trailer maybe you could reply back. Even if you don't have a like trailer i would like to hear your thoughts. Thanks for the help.

Steve

[traveldawg]

Most of us experience this problem. My feeling is that the tanks GD uses and the way they plumb the system is prone to poor dumping and residual water/waste.

I raise the front of my rig as much as I can when dumping.

[AZMike]

I was very concerned about this issue shortly after I bought mine, to the point that I had mine checked out during our first trip. After much research and careful analysis I have come to find out that the black tank exit is on the front of the tank on the street side. When I dump I try to have the curb side higher. If I'm at a dump station, and there is no one waiting behind me, I I raise the street side with some 2x6's that I carry with me. Don't be concerned with the black tank indicator. They always lie.

[sande005]

Very approximate calculation:
Using the GD parts lookup on their web site for the 2600RB, the tank is 29x57x8. So 13,224 sq. in or 293 sq in per gal. With one inch of "stuff" still left, that works out to about 2.5 gal still in place. About 5% of the total 45 gal capacity.

Not something I would ever worry about.

On my slightly different model, for a really thorough flushing, 3 partial fills doesn't come close. It is surprising how long there continue to be solids showing up. If I'm being really thorough on the last dump before it goes to sleep for the winter, it can take up to 7-8 repetitions of a combination of black tank rinse, fills and flushes before I stop seeing bits and pieces.....but during the active season, I don't go through near that intensive of a rinse/repeat.

An add on Valtera valve on the discharge end is a great addition, to stop the cup or two of fluid that always seems to come out when taking off the cap when hooking up!