Domakihub Green pool? How to clear it fast
Algae turns a pool green within a day or two. Here's how to get clear, blue water back — step by step.
Reviewed by Domakihub pool pros · 2026-06-22 · 5 min read
A green pool means an algae bloom — usually after a heatwave, heavy rain, or a few days without filtration or chlorine. The good news: most green pools clear in 24–72 hours without draining, if you treat them in the right order. The video above walks through it; below is the same process as a checklist you can follow at the poolside.
Why your pool turned green
Algae thrives when free chlorine drops and the water warms up. Once it blooms, it clouds the water and clings to the walls and floor.
Two numbers decide how fast you recover: pH (algae resists treatment when pH is high) and free chlorine (your weapon to kill it). Get those right and the rest is brushing, filtering and patience.
What you'll need
A test kit or strips, pool shock (calcium hypochlorite or liquid chlorine), a pH reducer if needed, a stiff pool brush, and optionally an algaecide and a clarifier or flocculant for very cloudy water.
Clear a green pool in 5 steps
- 1
Test and balance the water
Test pH and adjust it down to about 7.2 if it's high — shock works far better at a lower pH. Check the filter is running and clean the basket/skimmer.
- 2
Shock heavily
Add pool shock late in the day (sunlight burns off chlorine). For a green pool, double or triple the normal dose. Run the pump continuously for at least 24 hours.
- 3
Brush the walls and floor
Brush everywhere — corners, steps, behind ladders — to break the algae loose so the chlorine can reach it and the filter can catch it.
- 4
Treat and filter
Add algaecide if the bloom is stubborn, or a clarifier/flocculant if the water is milky. Keep the filter running 24/7 and backwash or clean it as it loads up with dead algae.
- 5
Vacuum and re-test
Once the water turns cloudy-blue, vacuum the settled debris (to waste if you flocculated). Re-test, rebalance pH and chlorine, and the pool should be swim-ready.
Rather have a pro handle it?
Get a vetted pool pro in your city — one number, booked in EN/EL/DE.
FAQ
- How long does it take to clear a green pool?
- Light green usually clears in 24 hours; a deep, swamp-green pool can take 2–3 days of continuous filtering and repeated shocking.
- Do I need to drain the pool?
- Almost never. Draining risks damage and a big water bill — shocking, brushing and filtering clears the vast majority of green pools without draining.
- How do I stop it coming back?
- Keep free chlorine in range, run the filter long enough each day in summer, brush weekly, and shock after heavy rain or heavy use.