Algae is the most common fouling issue dock owners deal with, and also the most underestimated. It looks minor compared to barnacles, but a slick layer of algae on a dock walkway is a genuine safety hazard.
Barnacle King treats algae removal as part of every dock cleaning visit because leaving it in place creates problems that go beyond appearance.
Why Algae Builds Up So Fast
Algae thrives in warm, humid environments with consistent sun exposure and access to nutrient-rich water. Florida’s climate checks every one of those boxes year-round.
Dock surfaces that stay damp from splash, rain, or tidal contact develop algae within days of being cleaned. Shaded areas under dock covers or near landscaping tend to stay damp longer, which makes them particularly prone to buildup.
The type of dock material affects how aggressively algae takes hold. Wood grain gives algae a textured surface to grip, and once it establishes in the grain, it’s harder to remove completely.
Composite decking resists algae better but still develops surface growth in consistently damp conditions. Concrete docks are somewhere in between, with porous surfaces that absorb moisture and encourage regrowth.
The Florida Fish and Wildlife Conservation Commission provides educational resources on algae types common in state waters, and many of the species that colonize dock surfaces are the same ones that affect submerged marine structures.
How to Remove It
For above-water dock surfaces, a pressure washer set between 1,500 and 2,500 PSI handles most algae effectively. Use a wide-angle nozzle and keep the stream moving to avoid gouging wood or etching composite surfaces.
On wooden docks, a lower setting with a fan tip is safer than a concentrated stream. After washing, some property owners apply a marine-safe algae inhibitor or wood sealant to slow regrowth between cleanings.
Scrub brushes with stiff bristles work for spot treatment between pressure washes. A mix of water and a marine-safe cleaning solution loosens algae without introducing chemicals that could harm the surrounding water.
Avoid household bleach or chlorine-based cleaners on docks near the water. They’re effective on algae but toxic to marine life and can damage wood finishes over time.
Below the waterline, algae forms the initial biofilm layer that barnacles and other hard growth settle on. Removing it regularly is the single most effective way to prevent heavier fouling from developing on your pilings and submerged framing.
This is where professional dock cleaning adds the most value, since a diver can address the full structure from surface to substrate in one visit.
Staying Ahead of It
Algae will always come back. The goal isn’t elimination, it’s management. A quarterly cleaning schedule keeps algae from building up to the point where it becomes a safety hazard or a gateway for harder fouling. If you’re noticing regrowth faster than your current schedule can handle, shortening the interval during summer months is usually enough to stay ahead of it.
Get in touch to set up a cleaning plan that matches your dock’s growth patterns and keeps the walking surfaces safe year-round.