Pool Water Doctor: Troubleshoot Any Water Problem
Don't waste hundreds of dollars dumping random chemicals into your pool. Select what your water looks or feels like below to get an instant root-cause diagnosis and a 3-step prescription to restore pristine clarity.
Step 1: What Does Your Water Look or Smell Like?
Click to DiagnoseDiagnosis: Active Green Algae Bloom (Chlorophyta)
Free chlorine dropped below 1–2 ppm, or Cyanuric Acid (CYA) is too high (>80 ppm), neutralizing your chlorine and allowing airborne microscopic algae spores to multiply rapidly in warm sunlight.
Adjust pH down to 7.2 using Muriatic Acid. Chlorine is 2x more potent at pH 7.2 than at 7.8. Scrub all walls, steps, and behind ladders with a stiff nylon pool brush to break algae biofilms.
Wait until dusk. Add 3 to 4 lbs of 68–73% Cal-Hypo per 10,000 gallons (targeting 20–30 ppm Free Chlorine). Dissolve in a bucket first for vinyl pools.
Keep pump running continuously. Once water turns milky white/grey (dead algae), add concentrated pool clarifier to help the filter capture dead microscopic cells. Backwash filter when pressure rises 8–10 PSI.
Never add algaecide while shocking! High chlorine destroys algaecides and renders both completely useless.
Fast-acting high-potency shock that annihilates algae spores without raising stabilizer.
Coagulates dead milky algae into clumped debris that your filter can trap.
Break the defensive bio-membrane on plaster and vinyl walls so shock can penetrate.
Calculate dosing based on your exact pool volume in gallons or litres.
The 3 Golden Rules of Pool Water Recovery
Whenever water balance goes wrong, amateur pool owners make the mistake of adding multiple chemical treatments simultaneously. Follow these three rules to solve problems faster without damaging equipment:
Chlorine loses 80% of its germicidal power if pH is above 8.0. Never shock until pH is between 7.2 and 7.4.
Direct sunlight destroys up to 50% of unstabilized shock chlorine within 2 hours. Always add treatments after sunset.
Adding algaecide and chlorine shock together cancels both out. Wait at least 24 hours between chemical additions.