Not sure how ice in the tank is going to affect the thetford toilet. If I understood what you were saying. I have a thetford electric flush toilet and I have added ice to the tank several times before I got smart and fixed the problem. I tried all the fixes put ice and cleaner in the tank at the top of a 4000 foot tall mountain and then drove the switchbacks down to the bottom. Every fix will cure the problem for a very very short period. I was at a tiffin rally and saw a lot of the people there had a person that worked on tiffins installing SeelevelII
Garnet 709 Seelevel II Tank Monitoring System
There were a lot of people having them installed. The guy ran out of units and time so I could not get one installed at the rally. I watched him install one and it was so easy I just bought my own and installed it myself. My friend and I installed it in about an hour and a half. The guy at the rally did it in about 45 min. I have had my Seelevel II installed for over a year and a half and I use my coach a lot. I lived in it for 5 months last winter and the gauges are still readable. The gauges also give you a lot better idea of how full it is. The indicator seems to read in about 6 per cent increments instead of 1/3, 1/2 2/3. The boards are a digital signal so you just put the new boards on the outside of your tank. Wire them together and then I just used one of the wires from my old tank sensor to hook the new monitor into. I put the new monitor by the old one ( The professional cut out a space in the middle of the old monitor to put the new one in) Another bonus is you can add remote monitors. I have one in my web bay so when I am filling the water tank I can monitor it without having to go back in the coach. I can also see how much black tank or grey tank liquids there are left while I am dumping.