Algae tutorial
Blackspot algae. Treat it properly.
Blackspot algae can be stubborn because it clings to surfaces and protects itself. This example guide focuses on brushing, sanitising, circulation, and persistence.
Before you start
Get the pool ready, then follow the steps.
These guides are written for everyday pool owners. Use the steps as a practical starting point, then test your water and adjust based on your own pool size, equipment, and condition.
01
Step 1
Confirm it is likely blackspot algae.
Blackspot algae often appears as dark dots or patches that cling to pool surfaces. It can be harder to brush away than ordinary green algae.
Stains, metal marks, and surface damage can look similar, so check before treating aggressively.
- Look for raised or stubborn dark spots.
- Check shaded and low-flow areas.
- Compare with stains that do not brush at all.
02
Step 2
Break the protective layer.
Blackspot algae can protect itself with a tough outer layer. Brushing helps break that layer so chlorine and treatment can reach the algae underneath.
Use the correct brush for your pool surface. Be careful with softer finishes.
- Brush spots directly and repeatedly.
- Use a stainless brush only where surface type allows.
- Keep circulation running.
03
Step 3
Maintain strong sanitising power.
Blackspot algae usually needs sustained chlorine and repeated attention. A single quick dose may not be enough if the roots remain in the surface.
Keep testing and maintain appropriate chlorine for your pool and stabiliser level.
- Test chlorine daily during treatment.
- Check CYA if chlorine is not performing.
- Brush again after dosing.
04
Step 4
Use Dazzle to support the wider water reset.
Dazzle can help support algae control, reduce phosphate load, and improve water clarity while you deal with stubborn spots.
It should be used as part of the overall process, not as a substitute for brushing blackspot directly.
- Dose according to pool size.
- Keep filter and pump working well.
- Remove debris and clean the filter.
05
Step 5
Stop conditions that let it return.
Blackspot algae often returns when chlorine is low, circulation is poor, or surfaces are not brushed regularly.
Once the visible spots are controlled, focus on water balance, brushing, and filtration.
- Maintain chlorine consistently.
- Brush problem areas weekly.
- Watch phosphates and debris load.
Pro tips
Small checks that make a big difference.
Brush first
Treatment works better when the protective surface has been disturbed.
Be surface-safe
Do not use an aggressive brush on surfaces that can be damaged.
Persistence wins
Blackspot algae can take repeated brushing and chlorine management.
Ready for the next step?
Dazzle your pool with a clear plan.
Use the guide, dose correctly, keep the water moving, and finish with clean-up, testing, and balance. When you are ready, choose Dazzle and follow the how-to-use guide for best results.
