Jim F Posted March 19, 2009 Report Share Posted March 19, 2009 I keep reading about MPS and its value as an oxidizing agent to help chlorine "do its job" I believe that using MPS will alter effective DPS chlorine testing afterwards, for how long I don't know What do you do to correct this, especially since some users, like Nitro, add MPS before a heavy use and check chlorine levels during the soak? Quote Link to comment Share on other sites More sharing options...
Nitro Posted March 19, 2009 Report Share Posted March 19, 2009 Chem Geek can explain this in more detail. Total Chlorine = Combined Chlorine + Free Chlorine. FC is what needs to be consistently above zero, and what we are most interested in. If FC gets too low for too long we will have serious problems. However, if CC (spent chlorine) get's too high (above 1ppm), it starts to give off bad odors etc. This happens when not enough Chlorine is used. Therefore we want to keep CC < 1ppm, by using plenty chlorine. MPS helps Chlorine oxidize waste, and therefore helps keep CC low. The issue is, once you add MPS, the CC reading is no longer valid. Keep in mind though, MPS will only stay in the tub for few hours to a day max. Hope that makes sense. Quote Link to comment Share on other sites More sharing options...
chem geek Posted March 20, 2009 Report Share Posted March 20, 2009 I think the concern was about the testing interference since MPS shows up as CC (and sometimes as FC when its very high) in the chlorine test. There is an interference remover here from Taylor, but some people have tried it and not found it to be particularly helpful. As Nitro noted, the MPS doesn't stick around very long if there are things to oxidize. Since the MPS is being used to supplement the chlorine, if you still go by the rule of measurable FC by the next time you soak, then you're still in good shape since it's most likely chlorine being measured at that point as any MPS that may still be around would likely show up as CC, if at all. Also, MPS at hot spa temperatures is a decent sanitizer -- better than metal ions alone though not as good as chlorine -- so measuring FC even if it were partly from the MPS would still be OK. Richard Quote Link to comment Share on other sites More sharing options...
Jim F Posted March 20, 2009 Author Report Share Posted March 20, 2009 many thanks to both of you Good explanations Quote Link to comment Share on other sites More sharing options...
General Beluga Posted April 13, 2009 Report Share Posted April 13, 2009 Chem Geek can explain this in more detail. Total Chlorine = Combined Chlorine + Free Chlorine. FC is what needs to be consistently above zero, and what we are most interested in. If FC gets too low for too long we will have serious problems. However, if CC (spent chlorine) get's too high (above 1ppm), it starts to give off bad odors etc. This happens when not enough Chlorine is used. Therefore we want to keep CC < 1ppm, by using plenty chlorine. MPS helps Chlorine oxidize waste, and therefore helps keep CC low. The issue is, once you add MPS, the CC reading is no longer valid. Keep in mind though, MPS will only stay in the tub for few hours to a day max. Hope that makes sense. Nitro, I'm going away for about a 5 week vacation. I hesitate draining my spa as I don't want the seals to dry our and develop leaks. I have a Sundance Spa with an ozone generator and I use N2 with MPS shock weekly and add a small amount after each use. l also add dichlor in small amounts weekly to keep FC above 1. Given this routine, I am thinking that I should be able to shock the spa good before I go and have the neighbor kid add about a tbs of dichlor each week to keep the spa fresh while I am gone. Do you think this will be sufficient or do you have additional directions that I might need to follow to avoid a mirky mess when I return for vacation Thanks, John Quote Link to comment Share on other sites More sharing options...
Nitro Posted April 13, 2009 Report Share Posted April 13, 2009 Nitro, I'm going away for about a 5 week vacation. I hesitate draining my spa as I don't want the seals to dry our and develop leaks. I have a Sundance Spa with an ozone generator and I use N2 with MPS shock weekly and add a small amount after each use. l also add dichlor in small amounts weekly to keep FC above 1. Given this routine, I am thinking that I should be able to shock the spa good before I go and have the neighbor kid add about a tbs of dichlor each week to keep the spa fresh while I am gone. Do you think this will be sufficient or do you have additional directions that I might need to follow to avoid a mirky mess when I return for vacation Thanks, John After double checking with Chem Geek, the Silver/Copper Ions in the Nature2 system should be enough to keep any runaway bacteria at bay. However, if it were me, I'd still have someone add either MPS or Chlorine to the tub once a week, just to be on the safe side. Also, give it a good shock (12 ppm) with Chlorine before you go, and after you get back. If you use Dichlor, just remember it will add CYA to your tub. You don't want to be adding a lot of Dichlor, if you already have CYA built up. You may want to use bleach instead. However, I don't know how old the water is, how much CYA is in there already, when you're due for the next water change etc. All those will be determining factors. Quote Link to comment Share on other sites More sharing options...
Nitro Posted April 13, 2009 Report Share Posted April 13, 2009 Also, I forgot to mention, you probably want to drop the temp down in the spa as low as it will go before you leave. Not only will you save on electric, the chlorine will last longer in the water. Quote Link to comment Share on other sites More sharing options...
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