Hi Peggie -- I was hoping you would stop by!
I have two identical Groco model K-H Hand-Operated toilets. They are probably circa 2001. I use no tank treatment at all. My boat spends most of her time in a slip, vacant. Once a year or so we go for a multi-week high seas passage
-- that's the only time the head sees any real use.
The head with no problem gets used a couple times a month (pee only), and goes overboard
through a Y-valve. The head with the blue/green stuff never gets used, but I occasionally pump salt water
through it and overboard
. I use that head area as a gear
Now that you mention it, the head with the color problem may have some of that orange dye in the holding tank
, from a marina visit many years ago. But the tank should be more or less empty. In any case, I should probably flush it out the next time I go offshore
(or visit the pump-out station).