In many parts of Australia, heavy rain can stick around for days. When that happens, your swimming pool usually needs a quick check-up.

A light shower normally won’t cause much trouble. But after a big downpour, it’s worth spending a few minutes making sure your pool water is still balanced and healthy.

Rain can affect pool water in a couple of ways. First, it dilutes the water. Second, rainwater can change your pool’s chemistry. Rain is often slightly alkaline and sometimes even acidic, which can shift your pH and alkalinity levels.

The good news is fixing things is simple.

Here’s a step-by-step guide to get your pool back to perfect swimming condition.

Step 1: Clean your pool

Heavy rain often comes with wind and storms. That usually means leaves, dirt, and debris end up in the water.

Start by skimming out any debris and giving the pool a quick clean. This helps your Bionizer system, filter, and pump run properly without anything blocking the process.

A clean pool also makes the rest of your water balancing much easier.

Check out this blog post for tips and tricks on pool maintenance and cleaning.

Step 2: Check your water level

After a big storm, your pool water level will often be higher than normal.

If it’s too high, you can lower it by running your filter on the backwash setting or draining a small amount of water until the level returns to normal.

It’s best to do this before testing the water.

Step 3: Check for phosphates

Rainwater can bring phosphates into your pool. Phosphates act like food for algae, which is why algae sometimes appears after storms.

To prevent this, test your water and add a phosphate remover if needed. This removes the algae’s food source and helps keep the water clear.

Step 4: Test the pH and total alkalinity levels in your pool water

Heavy rain can shift your pH and total alkalinity levels.

Use your pool test kit and adjust the water until it’s back within the recommended range. Balanced water helps your sanitising system work properly and keeps the pool comfortable to swim in.

If you’re using the Bionizer pH Boss, it will automatically help maintain your pH level. You may still need to adjust the total alkalinity with buffer or sodium bicarbonate if levels have dropped.

What about calcium?

Rain usually doesn’t change calcium levels much. However, if you haven’t tested them recently, it’s a good idea to check.

Low calcium can sometimes affect copper readings, which may lead to inaccurate results when testing your Bionizer system.

Step 5: Test the copper levels (or other sanitiser levels)

Once your pH and alkalinity are balanced, check the copper ion level in your pool.

Rain and storm runoff can introduce contaminants into the water. Your pool’s sanitising system works harder during this time, which may cause the copper level to drop slightly.

If your copper level is low, simply use the boost function on your Bionizer to bring the copper ions back to the recommended level (see page 18 of your Bionizer Instructions Handbook for boost mode).

Optional step: Oxidise the pool water

If your pool water looks a little cloudy after heavy rain, an oxidiser can help clear it up.

You can oxidise your pool using:

• A small dose of chlorine
• Potassium monopersulphate
• Hydrogen peroxide

Add the oxidiser in the evening and run your pump for several hours. In most cases, the water will look clear and sparkling again by morning.

For a more automated option, an Eco-Oxidizer can help continuously break down contaminants that cause hazy water.

After the rain, back to swimming

Once your water levels are balanced again, your pool should be clear and ready to enjoy.

A quick check after heavy rain can prevent bigger issues like algae or cloudy water later on. Spend a few minutes on these steps, and your pool will stay fresh, clean, and swim-ready.

Enjoy the water!