Pool chlorine guides
Free chlorine (FC) is the front line of water safety, but getting it right is more nuanced than just adding liquid and hoping. FC disappears faster in hot weather, your CYA level sets the minimum you actually need, and combined chlorine — the gap between TC and FC — tells you when there's a problem chlorine alone won't fix. These guides cover the full picture: how to read your numbers, why FC vanishes overnight, which chlorine type to use, and the FC/CYA relationship that determines your real target.
FC/CYA Chart: How Much Chlorine You Need
Your chlorine target depends on your CYA. Use this chart to find the right FC minimum and avoid algae.
Pool Chlorine Levels Chart
Clear reference for FC, TC, and CC readings. What range to aim for, what's too high, and when to act.
Free Chlorine vs Total Chlorine
Your test kit gives two chlorine numbers. The gap between them is a warning sign most pool owners miss.
Pool Chlorine Too Low? Causes and How to Fix It
FC below target means algae, bacteria, and cloudy water. 6 common causes and the step-by-step fix.
Why Won't Chlorine Stay in My Pool?
Add chlorine and it's gone the next day? 7 causes — from low CYA to invisible algae — plus the overnight test that tells you exactly what's wrong.
What Causes High Combined Chlorine?
That strong chlorine smell isn't too much chlorine — it's chloramines. 6 causes of high CC and the breakpoint fix.
How to Raise Pool Chlorine Safely
Liquid, granular, or tablets — each works differently. The right method and dose based on your CYA level.
Does Liquid Chlorine Raise CYA?
No — and knowing which chlorine types do raise CYA is the key to keeping your pool chemistry balanced all season.
Liquid Chlorine vs Tablets: Pros and Cons
Both sanitize, but they affect your water differently. The CYA buildup from tablets is what most owners miss.
Track your FC/CYA ratio over time
PoolChem Tracker shows your FC trend against your CYA target — so you can see when FC is slipping before it becomes a problem.
