Type in whatever readings you have — leave the rest blank — and get a grade on each, plus your fixes in the order that won't undo each other.
Grades use widely accepted residential targets; your equipment manuals win on specifics. Fix links open the right calculator with your numbers already filled in.
Why the order matters
Pool chemistry is a chain: chlorine's killing power depends on CYA, pH drifts wherever alkalinity pushes it, and alkalinity moves every time you adjust pH. Fix things in the wrong order and you'll chase your own adjustments for a week. The report card sequences your fixes so each one stays fixed — sanitizer first because safety doesn't wait for perfect balance.
Reading your report
✅ means leave it alone — resist the urge to nudge numbers already in range. ⚠️ means off but not urgent: fix it this week. ❌ means it's either a safety issue (no chlorine) or actively causing the other problems (very high CYA muting your chlorine). One reading the card weighs specially: free chlorine is graded against your CYA, not a fixed number, because 3 ppm is fine at CYA 30 and inadequate at CYA 80.
The single most common report
Low chlorine, high pH, everything else fine — the default summer drift. Sun burns chlorine while aeration pushes pH up. The fix is the first two lines of your plan: dose chlorine tonight, a measured shot of acid tomorrow, retest in two days. Ten minutes, four dollars, and the water never gets a chance to turn.
Frequently asked questions
What order should I fix pool chemistry in?
Sanitizer first, always — chlorine protects swimmers while you sort the rest. Then pH (comfort and equipment), then alkalinity (it stabilizes pH), then stabilizer (CYA), then calcium and salt. Fixing them out of order means re-fixing: pH moves when you adjust alkalinity, and chlorine's strength depends on CYA.
What are the ideal pool water levels?
Typical targets: free chlorine scaled to your CYA (roughly 7.5% of it, minimum ~3 ppm), pH 7.4–7.6, total alkalinity 80–120 ppm, CYA 30–50 (60–80 for salt pools), calcium 250–450 for plaster pools, and salt wherever your generator's manual says, commonly ~3,200 ppm.
How often should I test my pool water?
Chlorine and pH two or three times a week in season (daily during heat waves or heavy use); alkalinity weekly; CYA, calcium, and salt monthly — they move slowly.
Are test strips accurate enough?
Strips are fine for quick chlorine/pH checks, but they're coarse for CYA and alkalinity, and they expire fast once opened. A drop-based kit (the Taylor K-2006 is the community favorite) is the upgrade that makes every calculator on this site more accurate.