Nobody likes a green, murky pool. Algae can turn your backyard paradise into a slimy mess fast, and once it takes hold, it’s a pain to get rid of. Luckily, with the right approach, you can clear up your pool and keep it that way. Let’s get straight to it.

Why Does Algae Show Up?

Algae love warm, still water with poor circulation and low chlorine levels—it’s basically the perfect holiday spot for them. If your pool starts turning green or feels slimy, that’s algae moving in. Sometimes it’s just a bit of green on the walls, other times it’s full-blown “swamp mode.” If you’ve had a bunch of rain, a pump issue, or just forgot to check your water balance, algae can take over fast.

Step 1: Check Your Water Balance

First, test your pool water. Algae thrive when your chlorine is too low, so grab a test kit (you can find them at Bunnings or Mitre 10) and check your chlorine, pH, and alkalinity.

• Chlorine: Should be around 1-3 ppm (parts per million). If it’s lower, algae see an open invitation.
• pH Level: Keep it between 7.2 – 7.6 for your chlorine to work properly.
• Alkalinity: Aim for 80-120 ppm to stabilise your water chemistry.

If these numbers are off, adjust them first before attacking the algae.

Step 2: Hit It with Shock Treatment

Now, let’s kill the algae properly. Regular chlorine won’t cut it—you need a pool shock treatment. This is a high dose of chlorine that wipes out algae fast.

• Buy pool shock from your local pool shop, The Warehouse, or a specialty store like Pool & Spa Warehouse.
• Follow the directions but use double or even triple the normal dose if your pool is seriously green.
• Dump it in at night (so the sun doesn’t burn off the chlorine too fast).
• Keep the filter running non-stop to circulate the treatment properly.

Step 3: Brush and Vacuum Everything

Algae love to stick to the pool walls, ladders, and steps, so grab a stiff pool brush and scrub every inch. Focus on corners and shady spots where algae hide.

After brushing, use your vacuum or waste setting on your filter to suck up the dead algae. You do not want it settling back in your pool.

Step 4: Keep Filtering

Your pool filter is your best friend here. Keep it running 24/7 until your water clears up. If you have a sand filter, backwash it daily. If you have a cartridge filter, clean it out often.

Step 5: Prevent Future Algae

Now that your pool is clean again, keep it that way:

• Test your water at least once a week.
• Keep chlorine levels right and shock the pool after heavy rain or lots of swimmers.
• Make sure your pump runs at least 8 hours a day to keep the water moving.
• Use an algaecide (you can find these at Pool and Spa Warehouse or Swimart) once a week as an extra defence.

What if the Algae Won’t Go Away?

If you’ve done all this and your pool is still green, the problem might be your filter. A dirty or clogged filter won’t clear out dead algae fast enough. Try replacing the filter media (sand, cartridges, or DE powder) and see if that helps.

That’s it! No one wants to spend summer looking at a gross, green pool. Stay on top of your water balance, keep your pump running, and don’t give algae a fighting chance. If you need supplies, check out your local Mitre 10 or pool supply store for chemicals and brushes. Now, go enjoy your crystal-clear pool!