No CYA after cleaning algae

Patsy B

Well-known member
Jul 12, 2020
47
Orlando/FL
Pool Size
10000
Chlorine
Liquid Chlorine
Hello finally got the pool crystal clear after the winter. Had Slammed it and it was high 23 - 30ppm Thursday. No CYA I can see the dot even with overflowing water out of the tube. Yesterday it was 10ppm, CYA the same no reading and today it is a light pink when I add the R-0870. I know it has no to low .ppm. I read some other threads and am confused. I guess it is high in ammonia? I do not want to waste anymore liquid chlorine (been very sunny/hot/humid). Is there something I can purchase at the pool store (Leslie's) that I can add to raise the CYA? I was hoping I could get my husband (dementia) in to get some form of exercise this weekend.
P.S. all other readings are good
 
Use dry chlorine stabilizer to raise CYA. Put it in a sock and tie it off. Hang carrot style in front of a return, or put it in the skiimmer.

Do you have pool math? Link-->PoolMath
 
Hello finally got the pool crystal clear after the winter. Had Slammed it and it was high 23 - 30ppm Thursday. No CYA I can see the dot even with overflowing water out of the tube. Yesterday it was 10ppm, CYA the same no reading and today it is a light pink when I add the R-0870. I know it has no to low .ppm. I read some other threads and am confused. I guess it is high in ammonia? I do not want to waste anymore liquid chlorine (been very sunny/hot/humid). Is there something I can purchase at the pool store (Leslie's) that I can add to raise the CYA? I was hoping I could get my husband (dementia) in to get some form of exercise this weekend.
P.S. all other readings are good
Did you have CYA before performing the Slam and now it’s all gone? What were and now are your other levels?
 
To be honest I don't know if I had CYA. I just know I had algae scrubbed slammed and then checked after water was clear. The other levels were in line with what is on the Taylor card I have the big kit (can't remember the name) Calcium Hardness, Total Alkalinity both were within the range for a manually chlorinated mason pool.
Don't have exact numbers.
 
FC = 0
PH - 8+ bright pink/red (used the small weekly test block for chlorine PH)
CH - 250
TA - 110
CYA - 0
I had pool math re-downloaded input these numbers. Its says ideal target level is 50? I did not enter that or maybe from last year and to add Dry Stabilizer like you suggested. Add 67oz or 4lbs, 3.0 oz to reach target. Once I reach target do I then add chlorine?
 
It is unlikely that you have ammonia with high pH.

Go ahead and add the dry stabilizer. Also chlorinate with enough liquid chlorine to reach the FC for a CYA of 30 using this Link-->FC/CYA Levels and keep it there. No need to wait for the stabilizer to dissolve...

at least 15 minutes after or before chlorine addition, reduce your pH with muriatic acid.

Everything else is fine.
 
Last edited:
My CYA is now 30 to 50. did it 2X 50 first time 30 second. Unfortunately I put too much chlorine in last night and now am at 21ppm. The PH taken with the cube is above 8.6 (bright pink). It is super sunny today so do I wait until chlorine ppm is down before adding muriatic acid? I have 31.45% muriatic - how much do I put in for my small pool? Again thanks all for your help. I've learned a lot. (which I hope to retain).
 

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The pH test is invalid when FC >10, and will show high with high FC.

Let the FC go below 10, then retest pH.

Use poolmath to help you with addition amount if you need it after retesting. Link-->PoolMath
 
You should be able to get better repeatability out of the CYA test.
When you do the CYA test, try this next time.

Once you have your solution ready, back to the sun, etc. Fill the vial to a line, say 80, lower the vial to your waist level and glance for the dot, you see it, add solution to the 70 line, glance, see it, repeat until you no longer see it with a glance. Then use the CYA value one step above the line you read. So if you stopped at 50, use 60 ppm CYA.

The vial is a non linear scale. So it is not reasonable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....
 
Okay my pool FC is 10ppm took 2 days for it to go from 20 something to 10ppm. My CYA is 40 and PH is 8.2. Pool math tells me all I need is dry acid to lower PH to 7.6. I also have muriatic acid instead? or both? I read the thread above and was a little confused with when I should have added acid.
 
I usually have no CYA when opening the pool in the spring, use the sock method each year, takes a couple weeks to get it up. pH started at 8.2, the stabilizer reduced it to 7.5. You might consider waiting until CYA is up to snuff before adding MA.
The CYA test mixing pool water with the melamine solution is a slow reaction. I usually mix it in the magnetic stirrer for about three minutes before pouring the test into the squirt bottle. After reading CYA in the tube, I usually pour the sample from the tube back into the squirt bottle and rerun the test just to verify.