How much CYA in Trichlor 3" puck?

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
23,625
SouthWest Alabama
Pucks come in different sizes. Common are 7 & 8 oz sizes. An 8 oz tablet will raise your FC by 2.2 ppm and your CYA by 1.3 ppm in a 25,000 gal pool.
 

Ted Y

Active member
May 8, 2012
38
Phoenix, AZ
Something I was wondering... My old 3" puck said the ingredients were 99% tricolor and the other 1% was not listed as CYA. Where does the CYA come from in the puck? Is it a byproduct of dissolution of the tricolor or an unlisted ingredient?
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
Trichlor is a chemical combination of chlorine and cyanuric acid in the same molecule (see Trichlor vs. CYA). The 1% are binders and minor impurities. This is why the relationship that for every 10 ppm FC added by Trichlor the CYA increases by 6 ppm holds true regardless of concentration of product or of pool size.
 

Ted Y

Active member
May 8, 2012
38
Phoenix, AZ
I was a BBB convert before. Now I understand exactly why. Once I learned about this pool chemistry stuff, it's not intimidating at all. Thanks guys.
 

tcat

Well-known member
May 30, 2012
821
Austin, TX
Old thread, but exactly what I was looking for. If I want to raise my CYA from 30 to 35 (or 40), all I need to do is chlorinate with pucks for a few days (since I have spares laying around), right? Maybe 4 or 5 days, turn off my Clorox feed and throw the plastic puck float in the pool (or run them through the auto-feeder). Don't want to buy CYA if I can use up old tablets.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
In your 15,000 gallon pool, four 3" 8-ounce tablets would increase FC by 14.6 ppm and CYA by 8.9 ppm. Tablets in a floating feeder typically take about a week to dissolve completely though it depends on the feeder. That's probably just about the amount you'll need to keep up with 2 ppm FC chlorine demand, but you should keep an eye on it and supplement if needed.