MONOPERSULFATE

[The_Pa._Lady]

What am I doing wrong?  Every time I shock my spa, and test the water, all is ok, except the MONO.  Why does it go Sky High after shocking?  And how do I get it down so we can go in?  

Thanks for the info.

[George]

What am I doing wrong?  Every time I shock my spa, and test the water, all is ok, except the MONO.  Why does it go Sky High after shocking?  And how do I get it down so we can go in?  

Thanks for the info.

Monopersulfate (MPS or Non-Clorine Shock) is an Oxidizer.  In a Spa sanatized with Clorine, tests for MPS levels are not accurate, you must subtract the Clorine effect from the test.  The test for MPS tests for the amount of Oxidizer in the pool or spa and since Clorine at high levels is also an Oxidizer it is picked up by the MPS test as an Oxidizer and you have a false high number.  MPS is a very effective Oxidizer and disipates quickly, usually within 30 minutes to safe levels.  There are testing methods available that subtract the Clorine effects from the MPS readings to give more accurate MPS readings but testing for MPS in Clorine sanatized tubs is difficult.  If you are shocking with the proper amount as directed by the Mfg and waiting 30 minutes, your levels of MPS should be safe as long as your Clorine test shows normal Clorine levels. Here is a link to more info on MPS.  MPS can also contribute to false Clorine or Bromine  levels until the MPS disipates.

http://www.poolspanews.com/2001/081/081chemclinic.html

[drewstar]

In an effort to help, I found this at  http://www.aquachek.com/articles.asp?AID=3&l=2

Testing Monopersulfate

Monopersulfate needs to be measured after each use. This ensures proper oxidation of wastes, yielding clear water for bather enjoyment. There are few kits available to test for monopersulfate. Almost all testing methods have chlorine interference, meaning that the chlorine level interferes with the monopersulfate test results. These tests actually depend on oxidation of an indicator by monopersulfate. Since chlorine is also a strong oxidizer, it usually causes false positive results in monopersulfate tests.

Hach has a subtractive testing method that gives an accurate monopersulfate value even in the presence of chlorine. First, it registers the total oxidizer value by a chemistry that detects both chlorine and monopersulfate. Second, the user completes a test that detects chlorine but not monopersulfate. The difference between the first value and the second value is the monopersulfate value. Accurate measurement of monopersulfate in pools and spas that employ mineral purification systems is easier. Because chlorine is not present in significant concentrations in these systems, test strips or kits that have chlorine interference give correct values despite the interference.

[hottubdan]

If you are shocking with MPS, when you test your MPS level will be sky high.  that's the point.  You can use the tub immediately.

[gturn]

What am I doing wrong?  Every time I shock my spa, and test the water, all is ok, except the MONO.  Why does it go Sky High after shocking?  And how do I get it down so we can go in?  

Thanks for the info.

I noticed from your other subject that you are Shocking with dichlor.  Your post here implied your were shocking with MPS. Dichlor can be used as a Shock but to shock with Clorine (dichlor) you need to raise the levels so high to Oxidise that it can take hours or days to get back to safe levels.  And if you are shocking with Dichlor and the clorine levels are OK after shocking, you must have had a lot of bacteria in the water to use up all that dichlor so fast. (could be possible since you only use dichlor weekly)

It is better to shock with MPS and use your dichlor after each use.  Some people say it is OK to get in the tub right after adding MPS, but you need to wait for 15-30 minutes with the pump on after shocking with MPS to be sure everyting is disolved, you don't want to get the undisolved chemicals on your skin.

If you are testing for MPS levels, they may be high because you said in your other subject you were adding it before each use and it is building up.  You only need to Oxidize (Shock with MPS) once per week.  Most people don't even test for MPS levels because the tests aren't accurate with clorine sanatized tubs.