Ne RV, How to keep the Grey/Black Tanks Fresh?

One thing I do is wash dishes in a dish pan, and pour that water down the toilet.. more water in black tank with some soap to keep stuff from sticking to tank and keeps yucky water out of grey.. also helps grey tank not fill quite so fast.. easy to do and not a complicated chemical mix to worry about... I have found the hospital dish pans are perfect size for my TT sink. and sadly I have a plentiful supply since my dad was in the hospital about 10-12 times during his last 2 years..