i would never think of putting pressure in my holding tank, the weight of the water in it is different than air pressure, air pressure will bow the tank out. the tank is sitting on something which takes the weight, the top does not.
i also would not use koolaid packs either, it is very acidic. we used koolaid to clean stainless toilets in the navy, as well as to shine pipes. food coloring would be safe thou, or go to a art supply and buy water color tints. another safe option is guys who work on pools have dyes they use to find leaks, it does not stain the pool.
i also would not use koolaid packs either, it is very acidic. we used koolaid to clean stainless toilets in the navy, as well as to shine pipes. food coloring would be safe thou, or go to a art supply and buy water color tints. another safe option is guys who work on pools have dyes they use to find leaks, it does not stain the pool.