06/02/2026
Your chlorine tabs may be causing your green pool.
Most 3-inch chlorine tabs are trichlor, which means they add chlorine and CYA/stabilizer every time they dissolve.
CYA is helpful because it protects chlorine from the Texas sunโฆ
โฆbut too much CYA โover-protectsโ the chlorine and makes it less effective.
Thatโs why your pool can technically show chlorine on a test strip and still turn cloudy or green.
A good target for most backyard pools is around 40 ppm CYA.
Pool chemistry expert Bob Lowryโs rule is simple:
Your free chlorine should be at least 7.5% of your CYA level.
So if your CYA is 40, your free chlorine should be at least about 3 ppm.
But if your CYA climbs to 100, now you need at least 7.5 ppm free chlorine just to keep up.
Thatโs why relying on tabs all season can create problems.
TL;DR: Tabs are useful, but they quietly raise CYA. Too much CYA makes chlorine less effective. Keep CYA around 40 and test it regularly.
Not sure where your CYA is? Message us โCYAโ and weโll help.
New Braunfels Pool Professionals
Zero-Stress Pool Careโข
TexasPools PoolTips CYA ChlorineTabs PoolChemistry