I hear many stories about the electronic gauges that read inaccurately because they have residue buildup on them. There are also as many products that people attest to that will help them stay clean. Not wanting the same fate for my gauges, I took a lesson from my brass tumbler and dishwasher when making my own drop-in concoction that has worked flawlessly. First, the lesson from my brass tumbler. I reload metallic cartridges, so they must be cleaned. I tumbled them in walnut hulls for many years, which I thought cleans them pretty well. I switched to tumbling brass in stainless steel pins, a bit of dish detergent, and water. This cleans the brass much better than walnut hulls, but there is still a film that dulls the brass. I wanted shiny brass! A friend of mine told me to get a surfactant, like Lemi Shine, put a bit in and try again. WOW did that brass come out shiny! Second, my dishwasher, a brand new machine that started to smell after a couple weeks of use, because of a film built up on the inside. Again, I noticed there is a "Spot Free" reservoir, which I have never filled. Just maybe a surfactant would do the same thing for the inside of my dishwasher? I bought liquid Jet-Dry and gave it a whirl. Again, WOW the inside looked like it was brand new and the smell was gone forever.
Now to our Airstream grey and black tanks. I drop in three items every time I dump the tanks. 1 dishwasher tablet, 1 Walex RV tank deodorizer tablet, and 1 teaspoon of Lemi Shine surfactant. If we are just sitting, there is no agitation, but I add everything anyway. We try to travel with up to 50% in the waste tanks. The additives slosh around and leave a squeaky clean tank. This combination seems to work like a champ, a flashlight inspection of what I can see shows no film buildup anywhere and we hardly ever notice a smell. My $.02
Now to our Airstream grey and black tanks. I drop in three items every time I dump the tanks. 1 dishwasher tablet, 1 Walex RV tank deodorizer tablet, and 1 teaspoon of Lemi Shine surfactant. If we are just sitting, there is no agitation, but I add everything anyway. We try to travel with up to 50% in the waste tanks. The additives slosh around and leave a squeaky clean tank. This combination seems to work like a champ, a flashlight inspection of what I can see shows no film buildup anywhere and we hardly ever notice a smell. My $.02