CYA during a SLAM

Sep 20, 2018
67
N TN
Pool Size
20000
Surface
Fiberglass
Chlorine
Liquid Chlorine
I'm on day 7 of a SLAM and I haven't seen much progress in several days, even though I've been adding chlorine every 3-4 hours during the day and have been backwashing when filter pressure goes up by 25%. I'm suspicious that CYA is below 30 now because of all of the backwashing, and that is why I'm not seeing much progress. I tested my water and I can barely make out the dot at 30 and it completely disappears at 20. Chlorine was at 9 ppms when this test was done. I took a water sample to a pool store to confirm my test results and was told that the CYA is 26. All of the other test results were spot on so I assume this is accurate.

If I increased the CYA by 4 ppms to 30, could this help the SLAM go faster? Is there any reason why I can't use Dichlor to quickly raise the CYA if I only add enought to get CYA to 30 according to the pool math calculator? PH is only 7.2 so I wanted to make sure that it was okay to use Dichlor. I really don't' want to mess with putting stabilizer in a sock and dangling it over a return if I could increase the CYA with Dichlor instead which is faster and easier to add to the pool. Here are my latest test results: FC 9, CC .5, PH 7.2, TA 50, CYA 20-30, CH 140.
 
I'm on day 7 of a SLAM and I haven't seen much progress in several days, even though I've been adding chlorine every 3-4 hours during the day and have been backwashing when filter pressure goes up by 25%. I'm suspicious that CYA is below 30 now because of all of the backwashing, and that is why I'm not seeing much progress. I tested my water and I can barely make out the dot at 30 and it completely disappears at 20. Chlorine was at 9 ppms when this test was done. I took a water sample to a pool store to confirm my test results and was told that the CYA is 26. All of the other test results were spot on so I assume this is accurate.

If I increased the CYA by 4 ppms to 30, could this help the SLAM go faster? Is there any reason why I can't use Dichlor to quickly raise the CYA if I only add enought to get CYA to 30 according to the pool math calculator? PH is only 7.2 so I wanted to make sure that it was okay to use Dichlor. I really don't' want to mess with putting stabilizer in a sock and dangling it over a return if I could increase the CYA with Dichlor instead which is faster and easier to add to the pool. Here are my latest test results: FC 9, CC .5, PH 7.2, TA 50, CYA 20-30, CH 140.
Ignore the pool store test. Their test tolerance (if they cleaned and calibrated the machine) is +\- 10ppm so 4ppm is bascially nothing.

Your FC being at 9ppm will make the SLAM take longer though. It needs to be bumped up to 12ppm as often as reasonably feasible.
 
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I've been brushing twice a day and have been bumping up chlorine to 12 ppms every 3-4 hours during daytime hours. The only reason it was 9 ppms this morning is because I hadn't added chlorine since 9 pm that night. If it won't help the SLAM go faster if the CYA is increased to 30, I guess I will wait to add more CYA when the SLAM is over.
 
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If it won't help the SLAM go faster if the CYA is increased to 30, I guess I will wait to add more CYA when the SLAM is over.
Always measure your CYA at the lines, not between the lines. Or always round up. Your CYA is 30. You are good to go...Slam On!

If you want it to go faster, check and replace FC every two hours.
 
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