CYA Recommended Range Confusion

RaptorRidge

Member
Jul 13, 2021
5
Alabama
Until recently, I do not believe I have ever had an issue with the CYA levels in my pool. After my weekly shocking of the pool and a day later, I tested my chlorine with my OTO test kit. Instead of yellow results mine were orange. Having never had an orange result I did a quick search and discovered that high CYA levels could be the cause of the orange result. Given this, I purchased a Taylor 2600C test kit. The first test results showed a FC of 12, CC about .2. As best I could tell, the CYA test was around 80 to 90 ppm. Believing these results for CYA were high, I followed instructions from here and drained my water down about 1/3. In the meantime, I did not add any shock or chlorine to the pool. To sum it up, by not adding any shock or chlorine while I was trying to reduce my CYA levels, my pool has turned green. I thought I was doing something wrong so I took a sample to my local pool store to see what their test results would show. Below is the test results they provided me with their recommendation of adding 6lbs of pH down. Other than that, they said my test results were fine???

WaterTest.jpg

Now I am really confused. I was working on a CYA range of 30-50 ppm. Today their results were 59 ppm and the recommended range they showed is 30-150 ppm. I asked the gentleman at the store, why their recommended range was higher than what I had seen on this forum and other pool forums. His answer, "that range is acceptable because of the FC result". I have been running my pump continuously, backwashing when necessary and monitoring my test results. However, my water is still green. Any recommendations or help is greatly appreciated. Sorry for the long rant and thanks for reading.
 

JJ_Tex

Gold Supporter
Bronze Supporter
Jul 17, 2019
2,524
Prosper, TX (DFW)
Pool Size
13000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Welcome.

First of all, stop going to the pool store and mixing advice from here and the pool store. That is a recipe for disaster as their ranges are different than here, their results are not consistent, and their ultimate goal is to sell you stuff.

What do your test results show? If the green is from algae, it is because the FC was too low in relationship to your CYA (see my signature for the link to the chart if you need).

Post up your results and we can go from there.
 

RaptorRidge

Member
Jul 13, 2021
5
Alabama
Thanks for the reply.

Results from my Taylor 2600C test kit.....

FC = 5.6 ppm
CC = 0.0 ppm
TC = 8.2 ppm

pH = 8.0
TA = 90 ppm
CYA = black dot disappears about 55 ppm maybe 60 ppm

These numbers are from today at 2PM CT. FC was higher earlier today at 8 ppm
 

JJ_Tex

Gold Supporter
Bronze Supporter
Jul 17, 2019
2,524
Prosper, TX (DFW)
Pool Size
13000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Nice work on the tests!
Ok, your FC is dangerously close to the minimum of 5 for a CYA of 60. See the chart in my signature if you need. Use liquid chlorine to get it to 9 and try to keep it in the 7-9 target range for most of the day.

Do you actively have algae in your pool? If that is the green then you will have to follow the SLAM process to completely get rid of it.
 

RaptorRidge

Member
Jul 13, 2021
5
Alabama
Thanks again for the reply. I have looked at the FC/CYA chart and am shooting for a target of 8.0. Yes, I have visible green algae. Will study the slam process. Thank you for the help and suggestions.
 
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