It is harder to kill than green algae for two reasons. It grows a protective outer layer that chemicals struggle to penetrate, and it puts roots into porous surfaces, so killing the visible part leaves the root to regrow.
How to remove it
- Brush every spot hard with a stainless steel algae brush. This is the step people skip and it is the one that matters. You are breaking the protective layer so chemicals can reach the organism
- Rub a trichlor tablet directly onto each spot after brushing. Direct contact with concentrated chlorine kills what the brushing exposed
- Add a copper-based algaecide, following the dose rate carefully. Overdosing copper stains plaster blue-green
- Review the finished system against the agreed scope
Expect to repeat it.
Why it keeps coming back
Old plaster, unsealed grout and rough patches give the roots somewhere to hide. On a tiled pool with sound epoxy grout, black algae rarely takes hold.
If black algae keeps returning to the same spots, the surface is the problem. Resurfacing or retiling is the permanent answer.
Prevention
Hold free chlorine consistently rather than letting it swing. Keep circulation reaching every part of the pool.
What matters in Dubai
Dubai heat, dust and strong sunlight change pool water quickly. Swimming pool maintenance needs regular testing and a clean circulation system. Chemical treatment works properly only when the pump and filter are doing their part.
What to check before work starts
The existing pool or room should be inspected as a complete system. Visible damage may sit beside a separate problem in the pipework, controls, waterproofing or ventilation. A written scope should identify the affected parts and state which surrounding surfaces need protection or opening.
The maintenance approach should match the pool finish and the installed equipment. Salt systems, automatic dosing and standard chlorination have different service needs, while shaded pools behave differently from exposed pools.
Related pool services
The subject may connect with swimming pool construction and swimming pool maintenance. Swimming pool repair can be relevant as well. Swimming pool tiling applies where the shell or finish is opened. Sauna installation and steam room work are separate wet-area services.
- Swimming pool construction and renovation
- Swimming pool maintenance and water care
- Swimming pool repair and equipment work
- Swimming pool tiling and waterproofing
- Sauna and steam room installation or repair