Maintaining high Cl due to high CYA

[Max Webster]

I've been debating whether or not to do a partial drain to lower my high CYA and CH levels, or just keep adding bleach to keep the FC levels in the range recommended by the Best Guess Chart. From a cost perspective, I believe keeping the higher FC level is best, but I'm concerned what is tolerable and safe for the swimmers. I'm adding roughly a gallon and a half each day (or just under 3 gallons every other day) to get back up to a ~10 ppm FC level. The water clarity has never looked better since using bleach and getting rid of the pucks a week and a half ago, and a Taylor K-2006 test kit to get accurate readings. I have recent readings I could post, but my main concern is.....is there a FC reading you don't want to be above, regardless of CYA reading, to be safe for swimmers? This is for a 23k IG gunite pool. (CYA continues to read 100+....about 35 drops and the dot is not seen).

Thanks!

[azhobbs]

Max,

Great questions--since I have the same predicament (cya 150ish, due to using pucks). My only difference is that I can hold 10ppm CL with only 1.5 quarts a day. My pool is 15K gunite. Let's let the experts chime in....

[duraleigh]

Max,

Can't answer your question directly...it's a subjective answer. If 25ppm is too much, isn't 24ppm ALMOST too much? If you can be in 20ppm for one hour safely, how about 10ppm for two hours...shouldn't that be the same exposure? So, it would be impossible to pinpoint a number and say this number is safe but 1ppm higher and it's not.

I can comment somewhat on your pool conditions. You appear to be consuming quite a bit more Cl than most posters on this forum. azhobbs usage is more typical.....you may have some organics still in your pool that shocking would clear up. Secondly, you don't post test results so I cannot comment on your calcium levels nor any of your other levels.

Lastly, I think that managing a pool with high CYA levels is troublesome. It presents you with problems just like the one you are asking about...how much chlorine is too much? Painful as it may be, I think biting the bullet and doing a partial drain to rid yourself of the high CYA makes pool managment (and especially algae management) much simpler.

[azhobbs]

Dave,

Thanks for that reply. My strategy is to limp along until October when I do a full rebuild of the pool. Then I will start fresh with the BBB method and then it is smooth sailing....

[Max Webster]

I appreciate the replies. In light of a clear pool, every reading I have out of normal requires dilution to correct. High CYA (100+), high Calcium Hardness (600), and Total Alkalinity (175, but down from 250 after first partial dilution). Still two months to go in the pool season here, so I'll try a 50% drain. Fill water is essentially 0 FC, .8 CC, 80 Calcium Hardness, Ph 8.0 and TA 70. A shock after refilling and maybe the FC maintenance won't be so high? I'll bite the bullet......