CYA Problems

[maureenq]

I tested my water yesterday (25,000 gal guinite pool)and the pool co. is here right now opening it up. I decided after last year when the pool co. opened and I purchased the "start-up chemicals" from them, not to buy them again since last year after they left I tested the FC and it was 0. Anyway, here are my #'s - FC,CC, TC -0
PH - 7.8
ALK - 120
Cal - 150
Cya - 55
Besides adding bleach, I think everything else looks ok, based on my #'s from last year. My cya has run the same all last year, but this year to cut down on bleach usage, I want to drain some of the water to see if that will make a difference. We have a community well, which still has to meet the water co. standards, but I assume I should have my reg. water checked first and see if this will cause a problem. I had it checked before and the only thing that was found was a high metal content, I know this since I had to buy a water system since my hair was turning green. Anyway, does this effect the cya or not? How much should I drain at a time? Since I had to have the water trucked in so as to not drain the community system, I can't add too much from my hose at a time. Also I usually use algacide 60 poly and think because of high metal content in my water, I should use some additive to help with this. Any advice would be appreciated. Thanks!!

[chem geek]

You will only be cutting down on your bleach usage with the lower CYA if you maintain a somewhat lower FC level with that lower CYA. At 55 ppm CYA if you were maintaining around 6 ppm FC with an absolute minimum of 3.7 ppm FC, then at a lower CYA level of 30 ppm you could maintain 3.5 ppm FC with an absolute minimum of 2.2 ppm FC. Since you may lose up to half of the FC over a day, the old way you might have added 5 ppm FC or so each day while with the lower CYA you will be adding around 3 ppm FC or so each day.

High metal content will not affect CYA or anything else except that it can cause staining. Since it turned hair green, this sounds like copper rather than iron. In either case, you can use a metal sequestrant such as Pool Magnet Plus or another brand.

You technically should not need to use PolyQuat 60 if you maintain chlorine levels, but you can use it as an insurance policy just in case your chlorine levels drop (say, if you forget to add chlorine for a day). If you get it at a good price, then it will ensure you won't get algae, but just keep in mind that it isn't necessary if chlorine levels are maintained.

Richard

[nater]

I would leave the 55 CYA alone. I've battled very high CYA (120+), and you can succesfully keep the pool clean and clear, even at very high levels by following the best guess chart. In my opinion, if it ain't broke, don't fix it. Especially with the issues it sounds like you have with fill water.

Have you considered a SWC unit? You're at the right cya level for one, and you won't have to lug bleach anymore...

[jagwire22]

Can someone straighten me out in lamens terms?

I thought had had most everything figured out, now I think I am confused again !!!


25000 gallons
Chlorine - pool store said 1ppm, Wal-Mart test kit said around 6ppm
(is the difference caused by one measuring FC,TC,CC and the other measuring FC,TC,CC) I have know idea!!!!!!!
CYA - 20
PH - 7.7
TA - 120

I know cya stabilizes the the chlorine level, but If it takes less bleach to sanitize a pool with a lower CYA then why would I want to raise my CYA to 30-50ppm like most people suggest.

Will I add less bleach in the long run with CYA at 30-50ppm compared to CYA at 20ppm?


Thanks in advance!!!!

[waterbear]

Can someone straighten me out in lamens terms?

I thought had had most everything figured out, now I think I am confused again !!!


25000 gallons
Chlorine - pool store said 1ppm, Wal-Mart test kit said around 6ppm
(is the difference caused by one measuring FC,TC,CC and the other measuring FC,TC,CC) I have know idea!!!!!!!
CYA - 20
PH - 7.7
TA - 120

I know cya stabilizes the the chlorine level, but If it takes less bleach to sanitize a pool with a lower CYA then why would I want to raise my CYA to 30-50ppm like most people suggest.

Will I add less bleach in the long run with CYA at 30-50ppm compared to CYA at 20ppm?


Thanks in advance!!!!

CYA helps prevent the chlorine from being burned off by sunlight. If it is too low you might go thorugh more bleach trying to keep the level up than if you have the proper level in your pool. If you have too much the chlorine becomes less effective at santizing and destroying algae. 30-50 ppm works well in most outdoor pools (60-80 in pools with a SWG).
Hope this helps.

[bcb1]

55ppm CYA is no big deal at all. Mine usually runs in the 70-80ppm range, and I've always had crystal clear water, never a problem.

I've often heard that 30-40ppm of CYA is the conventional wisdom, but I can tell you for sure that twice that amount works just fine. I've been at the pool store and those guys have told me that they only have seen "chlorine lock" problems when the cya level is in the 150-200ppm range.