The Reefer's Guide to Keeping Nuisance Algae in Check

In this guide

Every saltwater aquarist ends up fighting some form of nuisance algae at some point. Rather than treating each outbreak as a separate emergency, it helps to understand the handful of underlying principles that govern almost all algae growth in a marine tank.

It almost always comes back to nutrients

Nitrate and phosphate are the two nutrients that fuel the vast majority of nuisance algae. They enter the tank through fish waste, uneaten food, decaying organic matter, and sometimes through the source water itself. Testing both regularly, in your tap or RO water as well as your tank water, is the single most useful habit an algae prone aquarist can build.

The core toolkit

• Water changes remove nutrients directly rather than just diluting them, and are the fastest way to bring a spike back under control.
• A properly sized and well maintained protein skimmer pulls organic waste out before it has the chance to break down into nitrate and phosphate.
• RO or RO/DI water avoids adding nutrients and silicates through your top off and mixing water in the first place.
• A refugium growing fast growing macroalgae such as chaetomorpha gives algae real competition for the same nutrients, and exports them from the system when the macroalgae is harvested.
• Good flow eliminates the low circulation dead spots where most nuisance algae gets its first foothold.
• Lighting duration and spectrum matter as much as intensity. Seven to nine hours a day is plenty for most fish only and mixed reef setups.

A clean up crew helps, but is not a fix

Snails, hermit crabs and algae grazing fish are a valuable part of ongoing maintenance, keeping new growth trimmed back. They are not, however, a substitute for addressing the nutrient and flow issues that caused the outbreak in the first place. A tank that relies purely on its clean up crew to manage a genuine nutrient imbalance will usually see the algae return once the crew is overwhelmed.

When to reach for chemical treatments

Algaecides and specific treatments exist for stubborn cases, but they should sit at the bottom of the list, used only after the underlying causes have been addressed, and always with caution around sensitive corals and invertebrates. For most Indian hobbyists working with modest sized home tanks, consistent water changes, a functioning skimmer, and sensible feeding will resolve the majority of algae problems without ever needing a bottle of chemical treatment.

Article content © S Vejay Anand. All rights reserved.