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

First one full toilet bowl of water.
Second one full toilet bowl of water with one pint of PineSol. It must be 7-8 gallons.
When outside temps are above 90 degrees I use one quart of PineSol because the high temps seem to "cook" our waste and produces some odor before the tank gets full.
Last nights low temp was 102 degrees. I'm using one quart PineSol each time right now.