How much liquid will cover the bottom of my black tank?

I would say 1 gallon.

I would give it 2-3, black tanks are usually flat and pancake like and have a lot floor (or bottom) space.

Put a bucketful in, whatever size of bucket you have handy.

Bill

After dumping, I have always gone ahead and put in whatever black tank treatment we're using, normally Odorlos, and add about 5 gallons of water. And let it slosh. If it's a longer period between trips, when we start out again, I'll go ahead and add some more treatment. We're minimal with the FW tank - since we rarely use it - but generous with the black tank water.

thanks but I sell plastic buckets, you don't want to know how many different sizes I have available LOL :B

Trackrig wrote:
Put a bucketful in, whatever size of bucket you have handy.

Bill

It will take quite a bit to have some cover the entire bottom IMHO.

I have one of those rv black tank flush devices that allows you to back fill the tank with water from the outside. Because of the way the tank pitches towards the outlet, it actually takes a good minute or two before you fill the outlet pipe with water. Then...and only then... will water actually be making it's way back into the tank.

One gallon added to the tank will most likely all flow down towards the dump valve and I would doubt that a typical drive would slosh it back into the tank enough to do much good.

One gallon of water covers 231 square inches of the bottom of your tank (1 inch deep).

How large is your black tank (length and width in inches)?

today 20 seconds filled my 2 gallon jug so 2 minutes is a good amount. I figured 5 gallons would be a minimum but of course that puts me 1/4 full.

I would also say 2-3 gallons. Why risk it becoming a potty cracker like substance, some of the water will evaporate, so better to have a little extra.

I use very little chemicals in the winter, more when it gets warmer out. The smell is only bad once it is above about 70F outside.

Another tip that I got from my RV salesman was not to add chemicals first. That is because there is a bend in the piping, and then the valve - all below the height of the tank. So if you where to add say 1 cup of chemicals first, then add a gallon of water, the chemical will end up next to the valve, and none would stay in the tank.

Fred.

The rule of thumb I have always heard is 1 gallon to fill piping and then roughly 10% of tank capacity. So in your case 3 gallons. No idea where the source of that rule of thumb came from but it seems to make sense with respect to keeping the tank bottom wet.