Tri-Chlor pucks and CYA

Mar 23, 2017
Edmond, OK
Just a question, but what is it about the pucks that make the CYA raise with constant usage? Is there actually cyanuric acid added to the pucks, is it a byproduct of the chemical reaction of the pucks or what? In other words, what is the mechanism that makes the CYA in your pool rise when using Tri-Chlor as your primary sanitizer?

If it's just an additive to the pucks, why not make pucks that don't have any CYA in them because they sure are a heck of a lot more convenient than lugging jugs of chlorine around. Just thinking out loud here.


TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
NW Ohio
Trichlor is short for "Trichloroisocyanuric acid". Chlorine is a gas, it must be attached to something to remain a solid and trichlor is the easiest of these to press in to puck form, but for every 1 ppm of FC added to the pool 0.6 ppm CYA is also added.


Well-known member
Jul 6, 2016
Memphis, TN
Had the same thought when I got started. It's not just an additive, it allows it be stable in a solid form. When adding chlorine to your pool, fact is you're gonna be adding something else with it. Whether it be CYA with trichlor tabs, calcium with Cal hypo or salt with bleach.

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