How to Prevent Algae in a Planted Aquarium

Algae is a balance problem, not bad luck. Controlling light, feeding, stocking, water changes and a clean-up crew keeps a planted tank algae-free as it matures.

Algae is a balance problem

The 2Hr Aquarist identifies the prime trigger for algae as organic waste combined with high light. Healthy, well-adapted plants strongly resist algae, while stressed or unhealthy plants get covered in it. Prevention is really about balancing your light against the plants' capacity to use CO2 and nutrients, and keeping waste down.

Control the light

Don't overfeed or overstock

• Overfeeding is called out by Tropica as the number-one cause of algae problems — feed sparingly.
• Keep the fish load light: Tropica suggests no more than about 1 cm of fish per litre of water, and preferably less.
• Keep temperature below 26°C; thread algae in particular thrives in warmer water.

Water changes and a clean-up crew

Tropica calls regular water changes one of the most effective tools against algae, because they stop nutrients accumulating. Keep a varied population of algae eaters, since different species graze different algae: Amano and Neocaridina shrimp, the Siamese algae eater (Crossocheilus), Otocinclus and nerite snails.

Let the tank mature

A mature tank is stable because of the microbial population it develops, notes the 2Hr Aquarist, and reaching good maturity takes roughly 6-8 weeks. Long-term, it is that stability — not chemicals — that keeps algae down.

Sources: Tropica Plant Guide, Preventing algae (tropica.com) and Starting a new aquarium (tropica.com); The 2Hr Aquarist, Algae and tank maturity (www.2hraquarist.com).