Camco 40227 TST Holding Tank Treatment - 1 Gallon

Nobody enjoys thinking about the black tank. But if you've spent a weekend in an RV or on a boat with a neglected holding tank, you already know the difference a good treatment makes. Camco's TST is the original-formula liquid that keeps waste breaking down and odors under control, and it's been the go-to for a lot of full-timers and weekend crews for years.

Here's what it actually does. The formula goes to work on solid waste and toilet tissue, breaking them down so they don't pile up and clog your dump valve or your sensors. It carries a deodorant to knock back the smell that creeps up through the toilet on a hot day. And it lubricates the tank sensors, which is the quiet hero of the whole thing. Gunked-up sensors are why your monitor panel reads full when the tank is half empty, and a treatment that keeps them clean saves you that headache.

It's formaldehyde-free, and that matters more than it sounds. Formaldehyde-based treatments can kill the bacteria in a septic system, and some campgrounds ban them outright at their dump stations. This one is safe for all septic tanks, so you can dump wherever you're allowed without worrying about what you're sending downstream.

Dosing is simple. It takes about 4 ounces to treat a full 40-gallon holding tank, and the bottle has a built-in reservoir so you can measure that pour without guessing or making a mess. One gallon goes a long way at that rate. The original scent is the classic clean smell folks have come to expect, nothing overpowering.

Who's this for? Anybody running a black tank they'd rather not think about. RVs, campers, travel trailers, fifth wheels, and boats with a holding tank all benefit the same way. It works in any season, so you're not swapping formulas between a summer trip and a fall one. If you're new to tank maintenance, this is about as forgiving as it gets. Add the dose after you dump, add a little water, and let it ride until the next stop.

A couple of honest notes. This is a maintenance treatment, not a miracle for a tank that's already badly clogged or has a sensor caked in old residue. For that, you'd want to do a deep clean first, then keep up with regular dosing so it doesn't get there again. And it's a liquid, so store it upright and keep it from freezing solid in winter storage.

The gallon jug is the size that makes sense if you camp or cruise more than a few times a year. It weighs about 9.9 pounds full and ships in a roughly 12 by 12 by 12 inch box. No batteries, no gadgets, nothing to break. Just a bottle that does one job and does it well, season after season.

If you want to get the most out of it, a little routine goes a long way. Start each trip with a fresh dose and a few gallons of water in an empty tank so the chemical has something to move around in. Keep a splash of water in the bowl between flushes to help solids reach the tank instead of drying on the walls. Dump when the tank reads about two-thirds full rather than letting it sit packed, and re-dose after every dump. Do that and you'll rarely fight an odor or a false sensor reading all season.

One more thing worth knowing. TST is made for the black tank, but plenty of owners keep a bottle around for the gray tank too, since the deodorant and waste-digesting action help cut the grease and food film that builds up from the galley sink and the shower drain. It plays nice with all standard RV and marine toilet setups, whether you've got a gravity flush or a macerator, so you don't have to match it to a specific system. Keep one in the storage bay and you've got tank maintenance covered for the whole trip, no matter where you end up parking or anchoring for the night.