Sewer Tank Flusher

I usually keep the drain closed for a little 15-20 seconds to get some water built up, with water coming in the flush and then open it and flush for about a minute.

Fill the black tank via the toilet before flushing.

Use the tank rinser with the dump valve open.

It is OK to close the dump valve for 1 or 2 minutes with the tank rinser running to build up a little bit of water, but don't walk off and forget it.

The reason they say to keep the valve open is in case you have a case of CRS (can't Remember Stuff) and turn on the flusher, forget about it and then you get the gusher in the toilet and you know where that goes.

OK, I have watched videos on YT about flushing the black tank. They seem to recommend using an inlet to fill the black tank so you get a big flush after the initial dump. To do that, you would have to be letting water in that inlet with the valve closed.

Most tank flushers have a "sprayer head" that squirts water on inside of tank. Sort of cleans up tank on inside. So your valve does not have to be closed for tank flusher to clean inside. But I do get better results if I let flusher run while I count to 60 with valve closed, and then open valve. Very important not to get distracted in the process or you might rupture tank.

Path1 said you might rupture the tank if you get distracted. NOT might BUT it WILL RUPTURE THE TANK. Just ask me how I know:o

My process:
Hook up flusher hose, close dump valve.
Turn on flush BUT DO NOT LEAVE, SIT RIGHT THERE.
After a couple or five minutes, open dump valve to see a some water run out.
Close flush valve.
After a couple of five minutes, open dump valve to see a some water run out.

Repeat as many times as you like or until the water runs as clear as you like.

Turn of flush valve.

I keep the valves open when I am using the black tank flush. I want to be sure I do not mess anything up. My black tank usually has lots in it when the valves are open so the stuff comes out in a rush. After the black tank is drained, I turn on the flush until the water coming out is clear - usually a few minutes.

I fill the black tank through the toilet before romping. When using a flusher, I leave the valve open. The reason it is recommended to leave the valve open while using the flusher is the spray is much more effective spraying directly on the tank walls. If the tank is filled with water while using the sprayer, all you're doing is filling the tank and not really spraying the walls. You can test this theory by filling a 5 gallon bucket of water, sticking your hand in the bottom then spraying it. You'll feel a much reduced spray of water.

And NEVER leave a hose connected there... Murphy has proven "s..t happens" :(

I can tell you how I do it and what I was told to do by a blank tank repair service. Why the service? 'cause I wasn't do it correctly the in the first place and developed the dreaded pyramid. The pyramid was concrete and had to be broken up with a high pressure wand. Anyway, I leave the tank valve closed and my other half stands inside and opens the toilet to start the flushing water. I turn on the flusher outside AND I STAND RIGHT THERE while the black tank fills. She watches on the inside and when she sees the water at the base of the pipe she knocks on the wall. When I hear the knock I immediately open the black tank valve and I get huge rush of water out and drain the tank which gets the tank pretty clean. We repeat this process one more time and then I let the tank flusher run for 3 minutes with the valve open. Done.