Adding water after dumping black tank

I dump a couple of toiletfills into the black tank along with the chemicals I use. Toiletfills: fill up the toilet then flush.

Good advice. When I am done with the black tank I put about 1/2 cup of liquid dish washer detergent in the toilet fill til full and flush. Then I fill the toilet a second time and flush. Good to go until next time the tank needs to be dumped. A hint while dumping the black tank. I have the DW fill and flush the toilet several times while the black tank valve is open. Helps get all of the solids out of the tank.

I add a couple of gallons to the black tank and sometimes squirt in bit of detergent along with the packet of stuff that's supposed to keep the smell down. The grey tank usually gets some added during clean up once we're home.

One thing to note, is that the black tank indicator may not be accurate. Sometimes ours still shows 2/3 full even after dumping. Sometimes it shows empty after dumping. Also, don't forget that water is the black tank's best friend. Make sure to use plenty or you'll wind up with a pyramid of yuck at the bottom.

Thats sound advise. I do not add water to the grey tank but put about 5 gallons in the black.
I run a hose in the bathroom window and add water directly through the toilet.

I don't have any type of tank rinser so as soon as my black and gray tanks are completely empty, my wife dumps 2-2 gallon containers of water into the toilet to to complete the rinse.