+ Home » + GENERAL » + Indoor Pool Owners Forum » + Can chlorine levels be reduced or zeroed temporarily ?      Next Topic   advanced Posted:  9/21/2009 8:37 PM #24865 janet Member       Total Posts:7 Last Post:9/26/2009 Member Since:9/21/2009 Subject: Can chlorine levels be reduced or zeroed temporarily ? Our oldest daughter is planning for her deb ball now and wants to use our pool room, which is big enough for an event that size. It will be a very formal event of course and I think she'll spend the next few months planning for that , looking at dresses, decorations and the whole lot :) Now, knowing her and her friends I'm pretty sure that they'll end up in the pool in their formal dresses and everything towards the end of the party. I think that will be ok but maybe some of the dresses could have a problem with the chlorine and since they'll all be in quite expensive dresses I am wondering whether one could cut out or at least drastically reduce the chlorine for the occasion ? Or would that make the water unsafe for swimming in ? Of course if it's a tradeoff we'd rather take a risk with their dresses than with their health. Reply Posted:  9/21/2009 11:00 PM #24867 chem geek Member Total Posts:854 Last Post:10/25/2009 Member Since:12/12/2006 Consider that most tap water has either around 1 ppm FC chlorine or 1 ppm monochloramine. However, expensive dresses with lace and thin material wouldn't be something I'd keep in pool water for very long. If you were using a small amount of Cyanuric Acid (CYA) in the water (say, 20 ppm), then I wouldn't be so concerned, but with your indoor pool I suspect there is no CYA in the water. So you could get the chlorine down to 1 ppm which should be enough to remain sanitary. Make sure your pH isn't too low -- have it at least 7.5 (but not more than 7.7). [Edited on 9/21/2009] Reply Posted:  9/23/2009 2:29 AM #24870 janet Member Total Posts:7 Last Post:9/26/2009 Member Since:9/21/2009 Thanks for your reply ! I forgot to mention how our pool is set up though, so I'm not sure how I can get to that level. Our pool has an automatic control system that adds liquid chlorine and hydrochloric acid as needed. On the control panel we can set three parameters: water temperature, pH value and then something called "Redox" which is somehow linked to the chlorine. The pH value is set to 7.6 and the system seems to keep that one stable as a rock. The "Redox" has a scale 0 through 10 and we have always kept it at about 2. Is it this one that I must put to a lower value then ? But how would that correspond to the 1 ppm that you mentioned ? I have never heard of any Cyanuric acid that you mention so I'm sure we do not have that one. So far we have never needed any chemicals other than what the system is adding and we've always had lovely water. I'm not sure of how bad the chlorine is for clothes. I've always heard that it's supposed to be bad but maybe it's a myth - I've ended up in the pool in dresses at some parties , including some that are supposedly dry clean only, and they've always been ok afterwards. I was just thinking that this time when they'll be in these very expensive dresses it could be a good safety precaution to lower the chlorine a bit, provided that it can be done safely. But of course if there's a choice it's better that they ruin a dress or two than that they get infections of some kind, so we must be confident that the water is safe for swimming too. Reply Posted:  9/23/2009 10:23 AM #24872 chem geek Member Total Posts:854 Last Post:10/25/2009 Member Since:12/12/2006 You'd have to get a chlorine test kit such as the Taylor K-2006 for a complete kit or the Taylor K-1515-A for just the FAS-DPD chlorine test (both are here) to see the Free Chlorine (FC) level, but even then this will only tell you what corresponds to your current "2" setting and not what would happen if you set it lower to "1". Reply Posted:  9/24/2009 8:29 AM #24874 janet Member Total Posts:7 Last Post:9/26/2009 Member Since:9/21/2009 Thanks, hmm that would mean that the only way to see what setting 1 corresponds to would be to test it... How long would it take after that I change it until I can see a stable result ? Is it only the free chlorine that is of concern when it comes to possible damage to clothes ? It's a pity that we can't set the chlorine level as such but I understand that this "redox" setting is similar to a chlorine setting, at least it adds more chlorine if you put it to a higher setting. When we first opened the pool it was set to 5 which was way too high and gave a noticeable smell of chlorine in the room. Now when it's on 2 there's no smell unless you get your nose almost down into the water. You can't notice anything in the room itself. And the water has always been nice and clear. Reply Posted:  9/24/2009 10:37 AM #24875 chem geek Member Total Posts:854 Last Post:10/25/2009 Member Since:12/12/2006 I don't know how long it will take for the chlorine level to stabilize at the new setting, but I suspect it will be a day or two since you are probably at a fairly low chlorine level now. Test the FC of your water at the current "2" setting. Since your pool is indoors, the daily chlorine usage is probably low, but may still be 0.5 ppm or more per day in which case if it's currently at an FC of around 2 ppm then it will take a couple of days to get to 1 if you shut off the chlorinator completely temporarily. Reply Posted:  9/25/2009 1:43 PM #24876 janet Member Total Posts:7 Last Post:9/26/2009 Member Since:9/21/2009 I tested with the test kit - I must confess I haven't done that for SO long even though I know you're supposed to do it from time to time. It showed 0.8 - 1.0 for chlorine and guess what - 7.6 for pH (that display never changes on the control panel and the test kit just confirmed how steady that one really is ). So maybe I am then already at the low end and should not reduce the chlorine any further, not even for that party ? I must say we've always had trouble free water - never any algue in the pool, never brownish water or so. The only slight thing one can notice from time to time is what looks like someone had poured a little milk into the water. It's so little that you can't see it in the daylight, but at night with the pool lights on you can sometimes just barely notice it. With a big family and a bunch of kids this pool gets a lot of use but I'm very happy with the way that it works. Our kids and their friends all love it and can stay in there for hours. Our oldest daughter and here friends are no exceptions and whenever there's a BD party or similar they usually end up in the pool. The only diffence is that for BD parties they're not in $ 1-5 k dresses so there's nothing to worry about.... Reply Posted:  9/25/2009 8:32 PM #24877 chem geek Member Total Posts:854 Last Post:10/25/2009 Member Since:12/12/2006 Yes, it sounds like you are all set to go without having to lower the chlorine level. Reply Posted:  9/26/2009 12:30 PM #24880 janet Member Total Posts:7 Last Post:9/26/2009 Member Since:9/21/2009 Yes, thanks for helping me in sorting this out. It also helped me to get to know the pool system a bit more - I've become lazy and just relied on the automatic systems... But it seems everything is safe now. I also happened to meet some of the other parents at a function yesterday and I mentioned my worries to them, they told me not to worry about it; it's no big deal with them in case something should happen to someones dress. Thanks ! Reply Posted:  10/9/2009 11:04 PM #24895 greenmatter Member Total Posts:7 Last Post:10/9/2009 Member Since:9/21/2009 useful tips/info..thanks H2O Lover! :) Reply Jump to: CHEMISTRY: Pool Chemistry Problems EQUIPMENT: Pool Equipment Product Reviews EQUIPMENT: Swimming Pool Equipment Problems GENERAL: Fun Pool Stories GENERAL: General Pool Forum GENERAL: Indoor Pool Owners Forum GENERAL: Pool Pictures GENERAL: Tech Row STRUCTURE: Swimming Pool Structural Problems        Next Topic