Green To Clean Pool Top 7 Tips

Last January we pulled up to a pool in Joondalup that had been clear on Friday and was thick green by Monday. The Pentair salt cell had faulted and with Perth pushing above 38 degrees, algae spores took over before anyone noticed. Where the Fremantle Doctor blows debris into backyards and hot weather runs for months, that timeline is normal. Once algae growth takes hold, the conditions create real health risks for swimmers.

We follow these seven steps on every green to clean pool job. Adrian has been running this process since 2003 with a Cert 3 in Pool and Spa Operations. Whether your swimming pool starts to turn green after a storm or has sat neglected for weeks, the following steps have it covered.

Seven Steps From Green To Clean

Green algae, mustard algae, it does not matter. The process to restore pool water starts the same way.

Step 1 Test A Water Sample (10 Minutes)

Take a water sample and test for free chlorine, ph, alkalinity, cyanuric acid and phosphates. You can grab test strips from your local pool store, though a professional reading tells you what strips miss. We aim for chlorine between 1 and 3 ppm and ph between 7.2 and 7.6. If cyanuric acid has build up above 50 ppm, chlorine locks. Adrian also checks for copper. Bore water around Wanneroo carries enough copper and iron to turn water green without algae.

Step 2 Skim And Remove Debris (15 Minutes)

Use a skimmer net to skim and remove leaves, floating debris and anything on the surface. Clean out the skimmer box and pump baskets. This bit of effort upfront stops organic matter feeding algae, which is what happens when the Fremantle Doctor dumps a street of leaves into your pool.

Step 3 Brush All Surfaces (20 Minutes)

Brush the walls, pool floor and every surface to dislodge algae clinging to grout lines and pebblecrete. Algae forms a biofilm that chemicals cannot penetrate, and this step is critical to breaking it. Stainless steel brush on concrete, nylon on fibreglass. Focus on corners and shaded spots where algae growth occurs first.

Step 4 Shock The Pool With Chlorine (5 Minutes Active, 24 Hours Circulation)

Shock dosing is the cure. Liquid chlorine oxidises active algae and organic contamination simultaneously. We dose at the appropriate dosage based on severity. A light green pool needs double the normal shock treatment. A dark green pool where you cannot see the floor? Five times or more. Adjust ph first because chlorine loses major effectiveness above 7.8. Run the pump for at least 24 hours after dosing.

Step 5 Run The Pump And Filter Continuously (24 To 48 Hours)

After shock treatment, the filter and pump must run nonstop to clear dead algae. We check the cartridge filter or sand filter pressure gauge and backwash as needed. On a recovery in Baldivis last year, Adrian cleaned the filter three times in 48 hours before the water shifted from green to blue.

Step 6 Vacuum And Clarifier (30 Minutes Active)

Once dead algae settles to the bottom, vacuum the pool floor to waste so it does not pass back through the filter. Set the multiport valve to waste, work slowly across the floor, then brush the walls again to rid the surfaces of anything left. If water is still hazy, add a clarifier to bind fine particles for the filter to trap.

Step 7 Prevent Algae Growth Year Round

Keeping algae gone requires regular maintenance and a bit of discipline. Test chemicals every week, brush and vacuum fortnightly, run the pump long enough for a full water turnover each day. Use a pool algaecide during the warmer months and a phosphate remover to cut the food source on bore water. For example, a pool we maintain in Scarborough has not had an algae outbreak in three years. These steps prevent algae growth in the first place and keep your pool swim ready year round. For more prevention advice, read our green pool guide.

Frequently Asked Questions

Questions we hear from Perth pool owners dealing with green water.

How Long Does It Take To Clean A Green Pool

A light green pool where you can still see the floor restores to crystal clear water in two to three days with continuous filtration. A dark green pool with a failing Zodiac or AstralPool chlorinator can take a week once the equipment is sorted.

Can You Swim In A Green Pool

No. Green water means the chemical balance is off and chlorine levels are too low to control bacteria. Treat it first.

Why Does My Pool Keep Turning Green

Recurring pool green problems typically trace back to a salt cell producing under 50% output, channelled filter media, or phosphates above 200 ppb feeding algae spores. If your pool turns green after rain or turns green overnight, the fix starts with finding which is the root cause.

Keep Your Pool Clean And Clear

If you have tried to fix a green pool and it keeps coming back, contact our team for professional green pool recovery. We treat the pool water, diagnose and repair the system and make sure it does not occur again. From how to fix a green pool to ongoing maintenance, we cover Burns Beach to Mandurah. Get in contact and we will have it sparkling and pool clean.