Brushing is the single most underrated step in pool maintenance, and the one most often skipped. It's not glamorous, but it's the primary mechanical defense against algae — and it takes less time than treating a pool that's already gone green. Here's why it matters and how to do it correctly.
Why brushing prevents algae
Algae doesn't establish itself overnight in open water — it starts on surfaces. Algae spores attach to pool walls, steps, and floor surfaces and begin forming a protective biofilm layer. This biofilm is what makes algae so difficult to kill with chlorine once it's established — the biofilm acts as a physical barrier between the algae and the sanitizer.
Brushing disrupts the biofilm before it can develop. When you brush a pool surface, you're dislodging algae cells before they can colonize and protecting them into open water where chlorine can reach and kill them. A pool that's brushed weekly very rarely develops visible algae, even in Florida's demanding summer conditions.
Which brush for which surface
Using the wrong brush can damage your pool surface:
- Plaster and pebble surfaces (Pebble Tec, Quartz): Use a stiff nylon brush or a combination nylon/stainless steel brush. The texture of these surfaces can tolerate more aggressive brushing. Stainless steel bristles help with calcium deposits and stubborn biofilm on plaster.
- Vinyl liner pools: Use soft nylon bristles only. Stiff or wire brushes will puncture or tear vinyl. Gentle circular motions rather than hard back-and-forth strokes.
- Fiberglass pools: Use soft nylon bristles. Fiberglass gel coat is smooth and relatively slippery for algae — it doesn't require aggressive brushing, but regular light brushing is still important in seams and steps where algae tends to start.
- Tile and step surfaces: A smaller detail brush works well for grout lines, step edges, and corners that a wall brush can't reach effectively.
Brushing technique
Attach the brush to a telescoping pole. Work methodically — start at the shallow end and work toward the deep end, brushing downward (toward the main drain) so debris settles toward the drain and gets picked up by circulation rather than dispersed through the water. Brush walls in overlapping strokes, moving from top to bottom.
Pay extra attention to:
- Steps and ledges — dead spots in circulation where algae typically starts first
- Behind ladders and handrails — areas the automatic cleaner misses
- Corners and coves where walls meet the floor
- Any shaded areas — algae establishes faster in lower-light zones with less UV activity
Frequency
Weekly brushing is the standard for most Florida residential pools. For pools with a history of algae problems, more frequent brushing (twice weekly) is worthwhile until chemistry and surfaces are stable. After storms, brush before running the filter to help settled debris and organic material get picked up by circulation.
Brush before adding chemicals when possible — particularly before shocking. Brushing before shocking exposes the algae cells that are developing on surfaces to the high-chlorine water that follows, making the treatment significantly more effective.
The connection to phosphates
When you brush debris off surfaces and it enters the water, the filter and chemistry need to process it. If phosphate levels are already elevated from organic accumulation, brushing can temporarily spike phosphate levels in the water column. This is another reason brushing and vacuuming work together — brush first, then vacuum to remove the loosened material rather than letting it settle again.