Thread Number: 88585  /  Tag: Modern Automatic Washers
STTP in Washer
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Post# 1131276   10/17/2021 at 01:50 (223 days old) by azchrisf (Glendale, AZ)        

Hello members,

I'm new here and wanted to ask a question. I have a new Maytag top load washer with the "auto-adjust" water levels and live in Phoenix, where our water is extremely hard. Recently I tried phosphates in my dishwasher and was amazed I found what we used 12 years ago before we had to start using citric acid (Lemishine) to get the dishes clear.

I bought a tub of TSSP and was wondering what the correct dose would be? I was thinking 3 tsbp, and I've heard of everything from 2 to 1/4 of a cup.

Many thanks!

Post# 1131302 , Reply# 1   10/17/2021 at 13:06 (223 days old) by eurekastar (Amarillo, Texas)        

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I would start with your suggested amount, then let the washer agitate for a bit.  After you feel it is thoroughly mixed in, then feel the water.  If it feels slick, you probably have enough or too much.  Then adjust accordingly.  Does your washer primarily use a spray rinse?  If so, you may not want to use too much, since too much STPP will make rinsing more difficult.

Post# 1131360 , Reply# 2   10/18/2021 at 11:03 (222 days old) by lakewebsterkid (Dayton, Ohio)        

I use 3T in our deep fill TL. It works well in our hard water.
In our FL, I always used either 1-2T depending on load size. Our water there was moderately hard.

Post# 1131375 , Reply# 3   10/18/2021 at 16:41 (222 days old) by quincyman (Oldsmar, FL)        

What is stpp?

Post# 1131381 , Reply# 4   10/18/2021 at 18:16 (221 days old) by appnut (TX)        

appnut's profile picture
Sodium Tri Poly Phosphate

Post# 1131816 , Reply# 5   10/24/2021 at 13:14 (216 days old) by azchrisf (Glendale, AZ)        

OK Thanks guys and gals!

Post# 1132209 , Reply# 6   10/28/2021 at 16:34 (212 days old) by azchrisf (Glendale, AZ)        

So, I did the recommended method and found the following. It was not until 4tbsp (about equal to 1/4 cup) did the water start feeling "smooth". Once the detergent was added (Gain), it felt very slippery.

Have I found the correct proportion, or doing something wrong?


Post# 1132456 , Reply# 7   10/31/2021 at 21:58 (208 days old) by eurekastar (Amarillo, Texas)        
Have I found the correct proportion

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It sounds like you got it! 

Post# 1132524 , Reply# 8   11/2/2021 at 12:13 (207 days old) by azchrisf (Glendale, AZ)        

Awesome. Thank you!

Post# 1132634 , Reply# 9   11/3/2021 at 21:23 (205 days old) by mark_wpduet (Lexington KY)        

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I never thought about using it in the washing machine. A long time ago, back when the dishwasher detergents formulations started to go non-phosphate and the detergent companies couldn't get their new formulations right for quite a while.....and people were using STPP OR buying institutional cascade. A few months ago, I was cleaning out my cupboards and found a 1/2 used container of STPP I bought from I thought, "hmm, let me use this up" even though I didn't think I really needed it. Well, I can totally tell using it vs not using it. Not the dishes being more clean, but the dishwasher itself looking more clean, the racks sliding easier, etc.

Post# 1132636 , Reply# 10   11/3/2021 at 21:33 (205 days old) by DADoES (TX, U.S. of A.)        
STPP-ified Laundry

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You've missed some discussions.  I've been adding STPP to both laundry and dishwasher (except not for Cascade Boil Out) for 10 years.

Post# 1132649 , Reply# 11   11/4/2021 at 04:09 (205 days old) by SudsMaster (East of SF, West of Eden, California)        

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I've been a big proponent of STPP here for as long, if not longer, as Glenn (Dadoes).

The water here is relatively soft, so I don't use much - a tablespoon - and then only for heavily soiled stuff like clothing.

The big advantage of STPP is that not only does it soften water, but it also does not form a precipitate with hard water minerals. TSP (or its evil twin, sodium carbonate) will form a precipitate, and should not be used in the washer. It's OK for rinsing down walls before painting, though.

The reason why STPP doesn't precipitate is because it forms a complex with water. However, if it has a weak side, it's that it will gradually decompose if left in solution for a while. So it should not be mixed with water in advance, but rather added in powder form at the start of the wash cycle. Preferably before the detergent.

Post# 1132670 , Reply# 12   11/4/2021 at 10:42 (205 days old) by mark_wpduet (Lexington KY)        
OK so

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why would adding STPP making rinsing more difficult?

Post# 1132736 , Reply# 13   11/5/2021 at 06:19 (204 days old) by PinkPower4 (USA)        
STPP and Dishwasher and Washer?

Around the time my old dishwasher went out and may have been why I thought it wasn't working is when STPP was removed from the dishwashing detergent. I never could figure out why my new dishwasher just wouldn't clean. It has an arm at each level and a rotating arm with a spinner at the bottom. I took a leap of faith and bought a six-pack of the Cascade Boil Out. Cascade Boil Out made the difference, and I have been happy with it since. However, the control board is going out, so I will have to replace soon.

Before the pandemic, I was also using the heavy duty detergent with phosphates. My washer and clothes seem to be getting clean with Tide with Bleach. For the clothes with odor, it seems like Tide 10x and OxiClean odor blasters works better (but it's only better not gone). I wonder if STPP would be useful in getting odor out? I don't use fabric softener or sheets.

This board has been a valuable resource :-)

Post# 1132763 , Reply# 14   11/5/2021 at 15:07 (204 days old) by azchrisf (Glendale, AZ)        


Have you tried baking soda, and I know Lysol makes a "Laundry Sanitizer". Is there bacteria or something in the clothes, or is is a body odor? I know just from browsing the board a lot of smart people on here may have good ideas for odor removal.

And yes, that's where I found out about Phosphates and is what I use in my Dishwasher, is Cascade Fryer Boil Out. If I need extra heavy duty cleaning, I add an extra Tablespoon to the Main wash dispenser. I know some of the older formulations were 12% or more Phosphates, I think Calgonite was one. I saw an original Cascade box that said 6.5% Phosphates, so Fryer Boil Out has slightly more.

Post# 1132774 , Reply# 15   11/5/2021 at 18:51 (203 days old) by PinkPower4 (USA)        

I use Lysol laundry sanitizer, and it (or vinegar) works well in the rinse cycle. I don't always catch the rinse portion of the cycle, and it takes an additional 15 minutes a load to let them soak.

I haven't tried baking soda, but I will keep that in mind. I was hoping to find something that would work in the wash portion of the cycle. They are my son's workout and work clothes so body odor. He is a college student so brings his clothes when he can, but I need to run them through using the shortest, effective cycle as possible.


Post# 1132775 , Reply# 16   11/5/2021 at 19:14 (203 days old) by DADoES (TX, U.S. of A.)        

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Borax in the wash has long been used as a freshener for cloth diapers and sweaty items.  I've been adding it recently to some loads.

Post# 1132806 , Reply# 17   11/6/2021 at 06:59 (203 days old) by Launderess (Quiet Please, There´s a Lady on Stage)        

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"why would adding STPP making rinsing more difficult?"

Softened water by any means, mechanical or substance, generally means using less soap , detergent, cleanser, etc...

Pure soaps will soften water as part of their nature, and of course detergent formulas contain builders to deal with water hardness. When water is softened by various means amount of detergent or soap should be reduced. Otherwise excess product will mean more rinsing work.

Post# 1132814 , Reply# 18   11/6/2021 at 10:29 (203 days old) by henene4 (Emden (Germany))        

The mechanism that makes you use more detergent in harder water also means softer water rinses worse.

The ions that make water "hard" interact with the surfactants and bind them up, basically.

So, during rinsing, hard water not only dilutes the detergent out but also binds some of the surfactants by quasi-chemical means.
Soft water can't do that.

Post# 1132939 , Reply# 19   11/7/2021 at 20:42 (201 days old) by SudsMaster (East of SF, West of Eden, California)        

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Where to get STPP?

Well, a decade or more ago, I found a chemical warehouse that agreed to sell me about 20-50 lbs of STPP (It came in a bag). I've since kept it in air-tight plastic bins, because over time it can degrade if exposed to moisture. So far, so good. Since I generally use only about a tablespoon, it probably will outlast me. LOL.

And STPP stands for Sodium Tri Poly Phosphate. The Poly part is the key - it enables the STPP to soften water and to bind to hard water minerals as well as mineral based soils to magnify the cleaning effects of laundry detergent. STPP was phased out of most consumer grade laundry detergents due to concerns over phosphate effects on water pollution (algae love phosphate). However, along the California coast, this really isn't a problem, since most water treatment/sewage plants empty their finished water into the ocean, which is usually full of phosphate anyway, and where algae is a good thing, not into a fresh water river or lake, where algae is not welcome. Want more info? Just ask.

Post# 1133419 , Reply# 20   11/13/2021 at 10:58 (196 days old) by drhardee ( Columbia, SC)        
Where to purchase STPP??

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The Chemistry Store, located just outside of my home town of Columbia SC, sells STTP. They are easy to work with, and their prices are quite reasonable.


Post# 1134045 , Reply# 21   11/20/2021 at 13:11 (189 days old) by littlegreeny (Milwaukee, WI)        
Is STPP supposed to clump?

littlegreeny's profile picture
I purchased some a while ago from Amazon and it clumps pretty badly when water is added. Is that normal?

Post# 1134112 , Reply# 22   11/21/2021 at 05:55 (188 days old) by Launderess (Quiet Please, There´s a Lady on Stage)        
No, it shouldn't

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Have STPP stored in gallon Ziploc bags and Rubbermaid containers that is not clumped in containers, nor when placed in water. There might be the odd clump per container, but nothing huge.

There are some complaints on Amazon that versions of STPP sold are of a more larger grain variety. That could be why you're having issues with clumping, as others have reported same.

STPP in my stash is a fine powder, again never had any issues with clumping

Post# 1134128 , Reply# 23   11/21/2021 at 12:33 (188 days old) by littlegreeny (Milwaukee, WI)        
Thanks Launderess!

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I have it stored in a Rubbermaid container as well and it's fine in the container but once added to the washer it turns into a hard clump. I must have been sold an inferior or perhaps imitation product? Maybe it's actually TSP?

I'm getting a new Miele in 13 days so perhaps it's better to just throw what I have out. I don't want to risk ruining my new machine.

This post was last edited 11/21/2021 at 13:08
Post# 1134132 , Reply# 24   11/21/2021 at 13:08 (188 days old) by littlegreeny (Milwaukee, WI)        
Perhaps it's just user error?

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I took a small glass of hot water and poured in about 1/4 tsp of the STPP and it dissolved immediately. There was no clumping or sediment in the bottom of the glass and the water felt slippery too.

Post# 1134133 , Reply# 25   11/21/2021 at 13:19 (188 days old) by henene4 (Emden (Germany))        

Some powders do that if you add them to water to quickly.
Adding them slowly or spreading them out thin onto the load before the machine starts to fill might work to.

Post# 1134148 , Reply# 26   11/21/2021 at 15:57 (188 days old) by eurekastar (Amarillo, Texas)        

eurekastar's profile picture

I think that may have something to do with the quality of the product or how it's stored.  I had that happen with some STPP that I bought off Ebay that came in large plastic bags.  However, I've never had that happen with STPP that I've purchased from Amazon, which comes in plastic tub. 

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