TechWriter wrote:
If you're going to dump chemicals down your tank(s), just use bleach. Cheap & fast acting.
Unfortunately bleach doesn't contribute to "cleaning" the tank walls or helping to break down the contents, especially hardened pyramids that may have formed over time due to prior inadequate tank maintenance. Lots of water, using a tank wand down the toilet throat to flush the black tank, and tank chems designed for the purpose will. One obviously can't wand the grey tank but I've found that using a GW tank treatment such as Walex Elemonate
does help a lot. :B