Seachem PhosGuard 250mL

Seachem PhosGuard is a highly efficient filtration media designed to remove excess phosphate (PO₄³⁻) and silicate (SiO₂) from both marine and freshwater aquariums. It plays a crucial role in maintaining a balanced and healthy aquatic environment by preventing algae growth, which can thrive in the presence of high nutrient levels. Phosphate and silicate accumulate from fish waste, uneaten food, and the breakdown of organic matter. In addition, water sources used for top-offs or water changes can also introduce these compounds, further escalating the potential for algae issues.

PhosGuard is made from aluminum oxide and features a spherical bead design, which maximizes water flow through the media. This shape ensures that water can efficiently pass through the filter media, preventing compaction that can occur with granular phosphate removers. As water flows through PhosGuard, phosphate and silicate are rapidly absorbed, leading to cleaner and clearer water, and thus a healthier tank environment.

When using PhosGuard, it’s important to pre-wet the media before use, especially in marine setups, to avoid generating excess heat. Rinsing the product with freshwater is recommended, and placing it in a high-flow area of the filtration system (such as a canister filter or media bag) will ensure maximum effectiveness. A standard dosage is 85 mL for every 200 liters of saltwater or 400 liters of freshwater. After 4 days of use, phosphate and silicate levels should be tested. If these levels haven’t dropped to the desired concentrations, the media may need to be replaced. However, once levels stabilize, PhosGuard can be left in place until it becomes exhausted.

PhosGuard is inert, meaning it does not release any absorbed phosphate or silicate back into the water, even after saturation. It can also be removed, dried, and reused if not fully exhausted, making it a flexible and cost-effective option for phosphate control. While it is effective in both freshwater and saltwater environments, Seachem advises against using it in phosphate-buffered freshwater systems, as this may interfere with the buffering capacity.