i use a charcoal and silver dual cartridge filter to treat any water that goes into my vans water tanks or if i am directly using water such as good bore water for immediate use, question..... if i was to filter tank water(Bat/bird poop ect) what would you add to vans tanks to keep it safe.there seems to be a lot of high priced commercial additives which appear to be mostly chlorine .is the pool stuff safe or do you need to pay the big $ for the stuff from the RV shop