kcolvin Posted May 1, 2015 Report Share Posted May 1, 2015 Help!! I have a problem. Leslie's Pool Supply is telling us to drain half of our pool to bring the TDS in to check. Our pool is about 10 years old. It was a salt pool until about a year ago, when we switched back to chlorine tabs. I would really like to avoid draining the pool but it is having algae outbreaks and also sometimes has trouble with high cyanuric acid, despite the cholrine levels being good. We never used to have any water problems. Here is a summary of our levels. Maybe you can help!! FAC 2ppm TAC 2 CH 360ppm CYA 80ppm TA 100ppm pH 7.8 Copper 0ppm Iron 0ppm TDS 3500 Pho 300 ppb Thanks!!! Quote Link to comment Share on other sites More sharing options...
chem geek Posted May 1, 2015 Report Share Posted May 1, 2015 You should not have to drain your pool. Since you had a saltwater chlorine generator, the TDS is mostly sodium chloride salt so is not a problem. Nevertheless, it would be a good idea for you to use winter rains to dilute the water or if you close your pool due to freezing conditions then you'll do a partial drain anyway. You are having algae outbreaks because your FC/CYA ratio is too low to prevent algae growth At 80 ppm CYA, you need to maintain a minimum 4 ppm FC in a saltwater chlorine generator pool or 6 ppm FC in a manually dosed pool. See the Pool School for more info. Quote Link to comment Share on other sites More sharing options...
kcolvin Posted May 1, 2015 Author Report Share Posted May 1, 2015 Thanks Water Wizard. We no longer have a saltwater chlorine generator. We replaced it with a chlorine tab "tube" about 8 months ago. I'm sure there is residual salt though. I probably need to do a partial drain. We just can't seem to keep the chemicals balanced anymore. The pool just doesn't sparkle like it used to. Meanwhile, I will visit pool school and up the chlorine. I just shocked the pool and will keep an eye on chlorine levels. Phosphates are high too. It seems silly to fix that if I have to do a partial drain anyway. Quote Link to comment Share on other sites More sharing options...
waterbear Posted May 3, 2015 Report Share Posted May 3, 2015 The problem is that your chlorine taba add 6 ppm CYA for every 10 ppm of FC added so your CYA will keep increasing and your pool will become over stablized. You were better off with the SWCG. My advice would be to stop the trichlor tabs and switch to liquid chlorine or bleach (sodium hypochlorite) or you will have to keep doing partial drains and refills to keep the CYA in check. Phosphates are a non issue if you maintain a proper FC level for your CYA level. . Quote Link to comment Share on other sites More sharing options...
chem geek Posted May 5, 2015 Report Share Posted May 5, 2015 Big thumbs up to what waterbear said. You took a huge step backwards going from an SWCG to using Trichlor tabs. You can recover by switching to using hypochlorite sources of chlorine such as chlorinating liquid or bleach or if you CH isn't too high then Cal-Hypo is OK for a while. Quote Link to comment Share on other sites More sharing options...
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