Green and cloudy pool water is a different problem to a pool that is just green. You are dealing with two things at once: live algae turning the water green and suspended particles reducing water clarity. The fix requires killing the algae and then removing the fine debris that makes it cloudy. One without the other leaves you with a pool that never clears and poses a health risk.
We see this across Perth every week, particularly after the Fremantle Doctor has been dumping dust into pools for days. Adrian has been treating cloudy green pools since 2003 with a Cert 3 in Pool and Spa Operations, and the first step on every callout is working out whether the cloudiness is dead algae, live algae, metals, or a filtration problem. Each needs a different solution.
What Causes Green And Cloudy Pool Water
Low free chlorine lets algae growth take hold while a struggling filtration system cannot clear the particles. When chlorine levels drop below 1 ppm in warm weather, algae spores multiply fast. The green tint is live algae. The cloudiness is fine particles, dead algae from a previous shock, or dissolved metals from bore water.
In Perth, bore water from the Gnangara Mound carries phosphates and elevated iron that feed algae and add cloudiness. We take a water sample and test for metals on properties around Wanneroo and Baldivis because treating for algae when the problem is copper wastes pool chemicals. The test results tell us which path to take.
When the pool’s ph drifts above 7.8, chlorine loses effectiveness, so algae grows even when you think there is enough. A clogged pool filter or short pump run times compound the problem because particles stay suspended. If your swimming pool is turning green and cloudy at the same time, the cause is almost always chemistry and filtration failing together.
How We Fix Green And Cloudy Pool Water
Green and cloudy requires treating algae first, then clearing suspended particles. Skip the order and you chase cloudiness for days.
Test And Balance First
Test for free chlorine, ph, alkalinity, cyanuric acid levels, phosphate levels and metals. Bring a sample to your local pool shop or use a reliable kit. Adjust ph level to the recommended range of 7.2 to 7.6 and alkalinity to 80 to 120 ppm before shocking. If cyanuric acid is above 50 ppm, chlorine is locked and you need a partial drain.
Apply A Superchlorinated Shock Treatment
Dose liquid chlorine at a high dose to lift free chlorine above 10 ppm. For a heavily cloudy green pool, Adrian doses at five times normal. Apply at dusk so the sun’s uv rays do not strip it. Keep the pump running continuously.
Brush Every Surface
Scrub the pool walls, pool floor and steps with a stiff brush to break the biofilm where algae hides. If you do not brush, algae in pebblecrete survives the chlorine and the pool stays cloudy.
Run The Filtration System And Monitor
Run the pump for 24 to 48 hours nonstop. On a sand filter, backwash when pressure rises 8 to 10 psi above clean. On a cartridge filter, hose the element when flow drops. Adrian cleaned the filter four times on a recovery in Joondalup last summer before the water cleared. A dirty filter recirculates the particles you are trying to remove.
Clarifier Or Flocculant And Why Filter Type Matters
This is where green and cloudy differs from just green. Once algae is dead, microscopic particles cloud the water. How you remove them depends on your equipment.
If you have a sand filter, a flocculant is the faster solution. It binds particles into clumps that settle to the pool bottom where you vacuum them to waste. Top up afterwards and adjust chemicals.
If you have a cartridge filter, do not use flocculant because the clumps clog the pleats. Use a clarifier instead, which binds particles into clusters the cartridge can trap. Adrian always asks what filter type a customer has because using the wrong product makes it worse. A pool in Scarborough we serviced had been dosed with flocculant on a cartridge system by a previous company. The cartridge was destroyed and the pool was still cloudy. We replaced the element, ran clarifier through, and had the water sparkling within 48 hours.
Vacuum, Retest And Adjust
Once dead algae and particles settle, vacuum the floor to waste. Retest and adjust free chlorine, ph and alkalinity. Maintain levels above 5 ppm until green fades. When the pool clears, return to normal range and monitor for the next week.
How To Prevent Green And Cloudy Water
Prevention comes down to consistent chemistry, adequate filtration and keeping debris out. Test pool water regularly in summer and after storms. Keep free chlorine in range. Run the pump eight to twelve hours a day in hot weather. Brush pool regularly and use a phosphate remover on bore water. For example, a pool we maintain in Hillarys has stayed healthy and clear for two years because the owner follows this routine. These habits prevent algae growth before it starts.
If you need advice on keeping your pool clear year round, read our green to clean pool guide.
Frequently Asked Questions
Do not worry if the process feels overwhelming. These are the questions we get asked most often.
Can Too Much Chlorine Make A Pool Cloudy
A high dose of shock can create temporary haze as it oxidises organic matter. This clears within 24 hours with continuous filtration. It does not need a dip in chlorine to fix, just patience and pump run time.
What If The Pool Looks Green But Chemicals Test Fine
Metals like copper can colour clear water green without algae. Common on bore water properties. Test for metals and treat with a sequestrant rather than more shock.
When Should We Call A Pool Technician
Call when the pool stays cloudy after 48 hours of correct treatment, when chlorine will not hold overnight, or when the green keeps coming back. These patterns usually point to equipment failure or a circulation problem. Treating green pool water without fixing the underlying issue is not a long term solution. Your local independent pool technician like us can diagnose what DIY misses. Contact our team for a green pool recovery callout and we will sort it properly. For a full walkthrough of fixing any green pool, follow our guide on how to fix a green pool.
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