You've got the wrong stuff.

TriSodium Phosphate = TSP = wrong

STPP = Sodium TriPolyPhosphate = right

While TSP IS a cleaning agent, often used for degreasing, washing driveways, paint-prep and such, STPP is the correct additive for introducing phosphates to laundry & dishwashing.

Chemically what is the difference? I questioned this with a chemist and was told that there was essentially none other than multiple industry names (now I question him). I had actually bought STPP and compared it to TSP by dissolving equal parts in water. Not scientific, I just wanted to feel the effects on the water. Not only do the powders look the same but their effects on the water were the same âÂÂto the touchâÂÂ, both felt like slick soapy water, same smell, and PH was identical. Even a bit of searching I find both described as used in soaps and detergents. DonâÂÂt tell me IâÂÂve been treating my wifeâÂÂs $200 jeans with driveway cleaner.

TriSodium Phosphate Synonyms: Sodium phosphate, tribasic; Sodium orthophosphate; Sodium phosphate; Trisodium orthophosphate; Phosphoric acid, trisodium salt; Sodium phosphate
Na3O4P

Sodium TriPolyPhosphate Synonyms: Sodium triphosphate; Triphosphoric acid, pentasodium salt; Sodium Phosphate Tripoly; STPP; pentasodium triphosphate; Pentasodium Tripolyphosphate
[Na5O10P3]n

Per info in the FAQ here on the Laundry Room Forum, TSP is a simple or "mono" phosphate and generates a precipitate, which is not a good thing for laundry use but not so much a problem washing a driveway. Avoiding precipitates is the reason for using STPP instead of other types of water softeners/boosters.

STPP is a "complex" phosphate compound and does not form a precipitate in the wash water. STPP decomposes into TSP over time with exposure to moisture (detergent packages instruct "store in a cool, dry place" which is to protect the product quality, whether or not phosphates are in it), and thus should be kept in an air-tight container for long-term storage.

Well thanks for the info! IâÂÂm going to dump that crap.

mieleforme, if you had measured the pH of the water after you had dissolved the phosphates you would have found that the TSP is far more basic (alkaline) than STPP. TSP has too much free phosphate too. I use it to dull old paint when I want to repaint a house or interior woodwork.

I have found that if you use too much STPP in your laundry, the rinse water will still have that slimy feeling to it. Your rinse water may be perfectly clear, but it still can have STPP residue in it.

So how much should you use? I've been using about 20ml of STPP per load.

20ml is around how much I use, a tablespoon or sometimes more.

When I was using Persil I used STPP with it and blended 2.5 parts Persil to 1.5 parts STPP. I used a 4 tablespoon dose of that blend on normal wash and double on heavy soiled washes like my work uniforms.

The amount of STPP one uses will be related to how hard your water is. So if you have soft water, 1/2 tsp may be enough.
If you have hard water 2 tbsps may be enough.
The way I judge STPP use is to feel the water. STPP will make the water feel slimy (soft). You want the wash water to be slimy and the rinse water not slimy. STPP will do nothing in the rinse cycle, only in the wash cycle where it helps the detergent get clothes cleaner.

Where do you buy the STPP ?? Can't find it online or at Home Depot.

Yes, it is available online. Probably at several sources. Search by the proper name "sodium tripolyphosphate." One source that's popular is TheChemistryStore.com.

may you please give me a good formulation of liquid laundry detergent using STPP as one of its ingredients

STPP is available through Amazon, also Ebay and it works great. No more spots, cloudy coatings or powdery coatings on glasses, dishes and silverware.

TSP can damage plastic or rubber parts in your washer. Do not use it in your machine.

Phosphates were taken out of detergents for environmental reasons. Try adding BIZ to your laundry instead. A Jet-Dry rinse aid basket hung from a rack in the dishwasher does a great job of producing spot free dishes and glasses.

There are many other sources of environmental phosphates. Detergents were targeted for removal for being an "easy hit."

I add STPP to every load, and Biz (powder) when stain/soil level calls for the added enzymes.

An easy target, yes as there is an awful lot of detergent dumped into the environment.

You are so right