Sludge forms as a result of fish and plant waste, and uneaten food. Sludge needs to be controlled as it can harbour disease-causing pathogens and add to the ammonia loading of the water.

Use when visible debris and sludge has collected on the substrate at the bottom of the aquarium. Add to the aquarium every week to maintain a cleaner aquarium. Regular water changes will then remove the digested sludge from the water.