Camco TST Orange Drop Ins Odor Treatment 15 Pouch Bag - No measuring, no mess. Just add one Drop-In to treat a 40 gallon tank. Harness the power of citrus to stop odors and break down waste. Fresh citrus scent. Contains 15 treatments. Environmentally Safe! Eliminates odors and helps break down waste in the RV holding tank; Ultra-Concentrated: just one drop-in treats up to a 40 gallon tank; Does not contain the toxic, formaldehyde-releasing ingredient bronopol; RV and marine approved; Safe for all septic tanks; Fresh citrus scent, 15 drop-ins/bag; Environmentally safe;