macgd016 Posted August 14, 2014 Report Share Posted August 14, 2014 I have a problem in that my good friend manages my pool for me whilst the house is rented out. He is a lovely man who is very dilligent and works hard but at some point most summers the pool goes a little bit cloudy and despite being shocked then goes green. I have explained many times that when this happens he needs to shock the pool and then keep the chlorine above 10 ppm until it is nice and clean again. The CYA is around 30 ppm and I have an automatic liquid chlorine pump so shocking and keeping the chlorine level high is very easy. HOWEVER, my pool manager (friend) insists that there is no algae in the pool and that it is just that the renters are using too much sun cream and therefore the pool needs flocking. Is there an article somewhere that I can send him that explains the procedure for clearing a milky/green pool as I seem unable to persuade him that the above is the right way to do it. Quote Link to comment Share on other sites More sharing options...
macgd016 Posted August 16, 2014 Author Report Share Posted August 16, 2014 Come on guy's, someone must have come across an article that explains that sun cream acts as a catalyst for algae growth and that filtration and shocking is needed to resolve it, or have I got it all wrong? Quote Link to comment Share on other sites More sharing options...
chem geek Posted August 16, 2014 Report Share Posted August 16, 2014 Oils in sunscreen are not readily oxidized by chlorine -- only some components are nitrogenous. Most sunscreen is removed by filtration and usually that just means running the pump for longer. Coagulation/flocculation should only be needed if the particles are smaller than what the filter can capture and such products are never used with DE filters, only occasionally with cartridge, and most commonly with sand filters. You can also Add DE to a Sand Filter to improve its filtration. Now if the cloudiness is from algae starting to grow, then raising the chlorine level to kill it off would be appropriate, but if the FC was always at least 7.5% of the CYA level, then the cloudiness is unlikely to be algae. Sunscreen does not promote algae growth. Chlorine at the appropriate FC/CYA ratio can kill algae faster than it can grow regardless of algae nutrient (phosphate, nitrate) level. Quote Link to comment Share on other sites More sharing options...
macgd016 Posted August 21, 2014 Author Report Share Posted August 21, 2014 Thank you once again for your valuable advice, I will print this off and give it to my friend, hopefully this will give him the guidance he needs Quote Link to comment Share on other sites More sharing options...
chem geek Posted August 21, 2014 Report Share Posted August 21, 2014 If the issue is primarily sunscreen and you have an oil film on the water that isn't getting to the filter quickly enough (perhaps because the pump is not on high), then you can use scum balls in the skimmer to help capture some of that surface oil.If you are going to be printing out advice for how to manage a pool, then look at the stickies at the top of this forum and also look at the Pool School. Quote Link to comment Share on other sites More sharing options...
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