Potassium Peroxymonsulfate

[cgin40]

I typically run about 2PPM of Combined Chlorine according to pool store testing. I have a K-2005 test kit which never registers any CC. The pool store advocates the regular use of Potassium Peroxymonsulfate to oxidize the Chloramines. This seems an attractive alternative to slamming my pool. My wife uses the pool every day so I would rather not take it out of commission for several days to slam it.
I would be interested in your thoughts about the use of Potassium Peroxymonsulfate.

 

[Donldson]

Do you find it the least bit strange that while you show 0 CC the pool store that sells MPS keeps finding CC that they say you need to buy MPS regularly to control?

Would you mind posting a complete set of results from your k-2005? That will shine a lot of light on your situation.

 

[chem geek]

Welcome to TFP!

If you follow the principles here at TFP, you will likely never have to shock your pool and you will likely never have CC above 0.2 ppm and certainly not above 0.5 ppm in your pool.

First off, you need to get your own good test kit such as the TFTestkits TF-100 or the Taylor K-2006 (see Test Kits Compared). Since you already have the Taylor K-2005, you can just get the FAS-DPD chlorine test. The CC from the pool store may be an incorrect reading. With the FAS-DPD test, you will be able to test both FC and CC with 0.5 ppm using a 10 ml sample but also within 0.2 ppm using a 25 ml sample. I suspect you have <= 0.2 ppm CC unless your CYA level is quite high.

If you were to use non-chlorine shock (MPS), then it can falsely read as CC in some tests (such as DPD) or as FC in the FAS-DPD test. There should not be any reason to use MPS in an outdoor residential pool.

If you actually did register some significant CC in your pool, you may not even need to SLAM it if the pool is normally covered. Just uncover it and expose the water to sunlight and that will usually take care of small amounts of CC.

 

[JoyfulNoise]

[EDIT]



Darn, should have hit refresh, chemgeek already answered the OP much more eloquently and completely than I did...Glad this isn't the OK Corral or else Quick-Draw chemgeek would have have put two bullets in me before I got a chance to draw....



[END-EDIT]

You need to be careful with MPS shocks. They will screw up your DPD-FAS FC/CC testing. There is a reaction between the MPS and the indicator (DPD) that makes the FC & CC's appear very high when in fact they are not. I believe Taylor sells a special reagent to use with the FAS-DPD test when MPS is present in the water.

Honestly, MPS is a very costly alternative to straight chlorine. If you have any significant CCs, that can be taken care of with a SLAM. MPS is just another high-cost, non-essential chemical that makes pool stores lot of profits and gives most users lots of headaches.