Total Chlorine & Phosphate Problems...What Should I Do?
by Bill
I have a 20x43 Lazy L in-ground vinyl lined pool (still orig liner). Pool was put in in 1998 so we are in the 14th season. I pay very close attention to the pool. I use primarily Bioguard chemicals. Pool was perfect for first 11 years then I started having chlorine demand problems. Two years ago was my first problem. I had no free chlorine in the pool. I became very confused with all the different advise I was receiving. One company said I had phosphates in the pool and needed to floc to get rid of them. The bioguard dealer did a water analysis and said I needed to put 50 pounds of shock in to get past the threshold. I did this and it took two full weeks in the middle of the season for the levels to come down enough to use (and the shock cost $500). But it worked and we got free chlorine back in the pool. This year I have a lot of total chlorine 4.5 - 5, I think, and just a little free chlorine - 2 ppm last week and down to .5 ppm now. The pool company again is telling me that the phosphate level is very high and that is the problem. I am very confused and not sure what is the right thing to do. Thanks for the question Bill I'll address the phosphates first. Phosphates are food for algae. If you go into your pool store and say you have phosphates and need a phosphate remover, they'll be more than happy to sell you a testing kit and several bottles of phosphate remover. The question is this: What's the chlorine for? It's to kill the algae and bacteria in the pool. If the chlorine is doing its job, then algae isn't a problem. If there's no algae, and your water is clear, then why would you need a phosphate remover? To the best of my knowledge, it's safe to swim in a pool with an elevated phosphate level. Next is the 50 lbs. of shock for a 35,000 gallon pool. When I shock the YMCA pool (80,000 gallons) I use between 23 - 25lbs. of granular chlorine. This will bring the chlorine level up to 20ppm. 50lbs. of shock in a 35,000 gallon pool is way too much overkill. You can go here to find the charts you need for a pool shock that is adequate for your pool: Swimming Pool Chlorine Pool Shock Pool Chlorine You were probably told that you have "chlorine lock" or something similar. This is told to pool owners when they don't know what else it is. Chlorine will go up and down. There really is no "lock". If you were locked in a 2.5ppm chlorine without needing to add any more chlorine, that would save you alot of chemicals. But it's not true. You need to test for chlorine and cyanuric acid (CYA), the stabilizer for your pool. The links above go into detail about that. Keep your chlorine level between 1.5 - 3.5ppm and cyanuric acid 30 - 50ppm. You can shock with Dichlor, which is a stabilized form of chlorine. The CYA can increase quickly when you use Dichlor, so you'll need to be careful. For every 10ppm of chlorine add with Dichlor, you'll also raise the CYA by 9ppm. I also recommend using a Taylor FAS-DPD K-2006 pool test kit. Pool Water Testing Water Testing Kit Hope this helps and good luck with your pool. Robert |
