How it works:
1. As a Biological Filtration Media - This is their most significant contribution to algae reduction. Algae thrive on excess nutrients in the water, primarily Nitrates (NO3) and Phosphates (PO4). By hosting a larger, more efficient colony of bacteria, clay pebbles in your filter help break down fish waste, uneaten food, and plant debris before they can decompose into these algae-feeding nutrients. This is called promoting a "low-nutrient" or "oligotrophic" environment where plants can outcompete algae.
2. As a Plant Growth Substrate. Used in the aquarium itself (especially in planted tanks, or as a soil cap for dirted tanks), they promote healthy plants, which is the best long-term anti-algae strategy. Their structure allows for excellent root oxygenation and prevents compaction, leading to stronger, larger root systems. The pores can absorb and slowly release liquid fertilizers added to the water column (root tabs are still best for root feeders). Healthy, fast-growing aquatic plants are direct competitors with algae for light, CO2, and the same nutrients (Nitrates, Phosphates). By giving plants a superior substrate, you help them win the competition, effectively "starving" the algae.
3. As a Detritus Trap and Maintenance Aid. When used as a top layer over soil or finer substrate, the large, round pebbles prevent waste from sinking into the anaerobic zones below. Instead, detritus sits on top, making it easy to vacuum away during water changes. Removing this physical waste manually prevents it from breaking down into nutrients.
● Nice solution to reduce excessive floating algae from aquarium water by direct filtration, or with help of colonized purifying bacteria.
● Highly porous surface structure of expanded clay provides very good colonization conditions for purifying bacteria.
● To be placed in filter media compartment of an external filter, submersible filter etc.
● Promoting vigorous plant growth to outcompete algae for resources.