First time pool, in Texas

Nicholas7

Member
Apr 8, 2025
11
Texas
Pool Size
12000
Surface
Plaster
Chlorine
Liquid Chlorine
Hi y'all,
Bought a house with a pool (12k, in-ground, plaster) in Feb this year. The pool has recently taken on a green hue!
After 1 month gap the pool guy turned up today and measured 0 chlorine, 7.6 pH, 120 TA, 500 CH and 100 CYA.
He added 3lbs dichlor shock (plus phosphate I think), and put chlorine tablets in the chlorinator.

I have purchased some liquid chlorine and ordered a Taylor test kit .

Reading on this site, I get the idea the dichlor shock will raise cya (already too high?) and lower pH.
Will this create a problem for me, or can I just wait and see what the kit recommends?
 
Welcome to TFP!!!

Use liquid chlorine. Add 5ppm PER DAY until the kit arrives.
Don't add anything else.
Post a full set of test results.
When you do the CYA test, if the CYA is 90 or higher, redo the test starting at #8 here:

If your CYA is over 60, then get ready to replace water. See no drain water exchange here:
 
Welcome to TFP!!!

Use liquid chlorine. Add 5ppm PER DAY until the kit arrives.
Don't add anything else.
Post a full set of test results.
When you do the CYA test, if the CYA is 90 or higher, redo the test starting at #8 here:

If your CYA is over 60, then get ready to replace water. See no drain water exchange here:
Thanks, I have only just seen your reply.
The TF-Pro kit arrived today and I have tested CYA twice (in line with your recomendation because the first test only got half way to the 100 mark). The second test =100, thus a cya of 200.
I also used the Comparator Block test and got readings of 0.5 and 1 in the Cl/Br column and 7.2 for pH.
These results seem to be worse than those reported by the pool guy on Tuesday, when he added Dichlor shock and tablets - CYA from 100 to 200. But the pool is pretty clear now.

How much liquid chlorine should I add each day to shock my 11000 gal pool?
Any idea roughly what percent of water should be drained (presumably before I add the chlorine).

Thanks again for your help.
 
How much liquid chlorine should I add each day to shock my 11000 gal pool?
We don't "shock" pools. We add enough chorine each day to maintain target for your CYA. Link-->FC/CYA Levels
Download pool math, it will help you with how much to add. Link-->PoolMath
You should use the FAS-DPD test for your FC test. (0870 and 0871). Use 10mL sample, and every drop is .5 FC.

Any idea roughly what percent of water should be drained (presumably before I add the chlorine).
You will need to exchange at least 75%, maybe more of your pool water to lower CYA to acceptable levels.

See "No drain water exchange" here: