Chlorine Level Too Low?

[sirsilent]

Hi

Recently I have problems to keep the chlorine level up in my pool. Yesterday for example I added 3 gallons of liquid chlorine (10%) and today the chlorine test shows 0 (I tried 2 different tests). The pool is roughly 30.000 gallons. How can that be? What am I doing wrong?

thanks

[knohe]

Hi

Recently I have problems to keep the chlorine level up in my pool. Yesterday for example I added 3 gallons of liquid chlorine (10%) and today the chlorine test shows 0 (I tried 2 different tests). The pool is roughly 30.000 gallons. How can that be? What am I doing wrong?

thanks

I work at a pool store in Maryland- I'd try using a granular shock that has a higher percentage. Try calcium hypochlorite. What might be happening is a chlorine demand/ chlorine lock. We've seen triple the amount in our pool store this year compared to last year. What happens is that pollen or other organic material (ducks, worms, leaves etc.) gets into the pool and releases ammonia. The ammonia builds up in solution and it reaches a point where HUGE amounts of chlorine are needed all at once. We had one family who had to add 125 lbs of 47% shock into the pool at once. I'd recommend finding your local pool store who can run a demand test that determines how much shock you would need to add. I know BioGuard dealers have an Accu-Demand test that does just that, and its been very helpful- we've gotten everyone so far this season who have had to trouble (about 80 or 90 people in the area) back into a clean, clear, sanitized pool.

[sirsilent]

thanks for the quick answer. It is true that a lot of leaves got into the pool during the winter while I was on gone vacation. I'll bring a water sample to a pool shop tomorrow. I hope they can figure out what the problem is because last time I did that they said everything is ok I just need more chlorine.

[knohe]

thanks for the quick answer. It is true that a lot of leaves got into the pool during the winter while I was on gone vacation. I'll bring a water sample to a pool shop tomorrow. I hope they can figure out what the problem is because last time I did that they said everything is ok I just need more chlorine.

Your pool probably looks perfectly clear, too. What we do is have the owner put in the recommended amount at around 6AM with the filter on RECIRCULATE (if you have a DE). This way its bypassing the filter so the pressure doesnt shoot up (which usually happens when you add a high amount of chlorine). Then with a liquid chlorine test (the kind where you fill to the fill line, then add 5 drops of OTO reagant) we have them test every 3 hours (so 9AM, 12PM, 3PM) etc for 24 hours. They want to see a DARK ORANGE or RED or even BROWN color it should be so high (the normal "ideal range is a yellow color at 3ppm). This way we know they are holding chlorine. If the colors starts to drop, 10 more lbs is put in the pool. Its a painstaking process, but worth it in the end because there are no more problems. After that 24 hour period, we begin rebalancing the pool (since shock usually raises pH) and let the sun burn the chlorine back to a safe level.

Check to see if there is a gap between your Total and Free chlorine when you get it tested tomorrow. If the total chlorine is much larger, its a SURE sign of this problem.

[knohe]

thanks for the quick answer. It is true that a lot of leaves got into the pool during the winter while I was on gone vacation. I'll bring a water sample to a pool shop tomorrow. I hope they can figure out what the problem is because last time I did that they said everything is ok I just need more chlorine.

Your pool probably looks perfectly clear, too. What we do is have the owner put in the recommended amount at around 6AM with the filter on RECIRCULATE (if you have a DE). This way its bypassing the filter so the pressure doesnt shoot up (which usually happens when you add a high amount of chlorine). Then with a liquid chlorine test (the kind where you fill to the fill line, then add 5 drops of OTO reagant) we have them test every 3 hours (so 9AM, 12PM, 3PM) etc for 24 hours. They want to see a DARK ORANGE or RED or even BROWN color it should be so high (the normal "ideal range is a yellow color at 3ppm). This way we know they are holding chlorine. If the colors starts to drop, 10 more lbs is put in the pool. Its a painstaking process, but worth it in the end because there are no more problems. After that 24 hour period, we begin rebalancing the pool (since shock usually raises pH) and let the sun burn the chlorine back to a safe level.

Check to see if there is a gap between your Total and Free chlorine when you get it tested tomorrow. If the total chlorine is much larger, its a SURE sign of this problem.

[sirsilent]

one more question, why does the filter pressure shoot up if I add chlorine? I have a DE filter but I don't think I have a RECIRCULATE option on it. The pool is a little green too and I just cleaned the filter a week ago but the pressure already increased by 10 psi.