Geo Method for us too, kind of. I make my own home brews. It's a turd tank, so not much will hurt it, as long as you're careful with chemicals and make sure nothing will hurt the valve seals. Lots of things will work. If you ever continue to have sensor problems, try Unique RV Digestit. You can use it for a regular tank chemical, but more importantly, you can use it to clean EVERYTHING out of the tank. It has directions for both. I haven't had to use it as the cleaner on mine, but have on other peoples rigs, and several years worth of stuff came out. The stuff works. Put the bottle of stuff in, fill tank up past the full sensor, wait however long it says (can't remember), then dump and flush. As a regular chemical, the way you use it will go against most stuff you have ever learned, but rest assured that works to. It has to have "stuff" to work, since it feeds off of it.
John and Rebecca Dickson
Emma-8 / Little John-5 / Iva-1+
2013 Ford F-350 Lariat FX4, CC LB PSD, DRW
2015 Jayco Jay Flight 28BHBE (#8)