I removed the seal on my Aqua Magic V, cleaned it and put it back in. I think the IV is similar. There were mineral deposits on the seal that I scraped off and the seal has been good for 2 years now, held the pink stuff all winter.
Its kind of a messy job but not difficult. Remove the toilet, take it outside and give it a good hosing someplace you don't mind leaving a small mess. Think of it as fertilizing the grass. The seal came out easily and went back in easily.
Hope you are not squeamish.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory
Same issue. I thought I had it once, but alas, no. Bought a new mechanism for it but was waiting until we got home to put it in. Long story short, decided to give the cleaning one more try. Got in to the grove with a bent coat hanger and scraped out a whole bunch of calcium and crude. Flushed it out and put in a large quantity of plumbers grease. It has worked flawlessly ever since. Got a mechanism if someone needs.
My SeaLand came with one of those disposable ladies finger nail files. The type with a sand paper like substance on both sides. The directions said to use this thing to clean the seal if it leaks. It does a great job and I still have good water retention after 8 years. I also make a special effort to clean the underside of the seal with toilet bowl cleaner when ever I'm performing that duty.
Scott, Grace and Wesly
2003 Dodge 3500 4x4, 6 speed Cummins (lightly bombed),
2004 Forest River 25RKS many, many mods.