CYA dropped, Trichlor okay to bring it back up?

Michael57

Member
Mar 30, 2020
16
Sacramento, CA
My CYA started at 50/60, but over the past couple of months it seemed to have dropped to 40, and then today it tested at 20. I'm quite surprised as we haven't lost that much water out of the pool.

Since I've been using liquid chlorine, is it okay to use some Trichlor that a previous owner left? I placed it in a floater, but do I need to run the pump non-stop until it's dissolved? How long does that usually take to dissolve?

My pH was about 7.7 and I've been lowering it with muriatic acid but if Trichlor will lower it that works. My FC was about 4 this morning...
 

Jeff J.

Well-known member
Aug 6, 2019
223
Staten Island NY
My CYA started at 50/60, but over the past couple of months it seemed to have dropped to 40, and then today it tested at 20. I'm quite surprised as we haven't lost that much water out of the pool.

Since I've been using liquid chlorine, is it okay to use some Trichlor that a previous owner left? I placed it in a floater, but do I need to run the pump non-stop until it's dissolved? How long does that usually take to dissolve?

My pH was about 7.7 and I've been lowering it with muriatic acid but if Trichlor will lower it that works. My FC was about 4 this morning...

If those results are accurate, I don't see any reason not to. It will raise your CYA and lower your PH, although your PH is fine. It will also lower your TA. Keep an eye on all those numbers, and stop using it if they get out of whack.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,151
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
If your CYA is at 20, you should use dry stabilizer/conditioner to raise it back to 50 ppm quickly. Pucks will be slow and the potential for FC to drop below the minimum is high.
Always test CYA monthly during the summer. I lose 10-15 ppm CYA per month. Elevated water temperatures accelerate its degradation.
 
  • Like
Reactions: setsailsoon

Michael57

Member
Mar 30, 2020
16
Sacramento, CA
Thanks for the help, I just tested again and I think it's actually 30... That makes sense on the elevated water temperatures. I'll pickup some dry stabilizer...
 

Jeff J.

Well-known member
Aug 6, 2019
223
Staten Island NY
Thanks for the help, I just tested again and I think it's actually 30... That makes sense on the elevated water temperatures. I'll pickup some dry stabilizer...

The CYA test is very tricky. Make sure you have your back to the sun, hold it at waist level, and just glance (don't stare) to see if you see the dot.
 

Oly

Gold Supporter
Jun 28, 2017
1,861
Fresno, CA
Pool Size
27000
Monitor your daily FC loss, and if not significantly higher then there is no immediate need to raise CYA from 30 to 40. Calculate how many 8oz tabs of trichlor you need to add 10 ppm and be sure to monitor your pH. No need to fully dissolve the tabs in one float and no problem pulling out the floater for several days and dropping it back in. Plan to add your normal liquid additions each day to keep FC in the zone or a few ppm above and test to confirm. Easy really.
 
Thread Status
Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.