Seachem PhosNet

• 1.41 mg phosphate per gram – the highest binding capacity of Seachem's three phosphate media, so less product is needed for the same nutrient load.
• Synthetic GFO, low dust – cleaner to handle and rinse than natural granular ferric oxide, and less prone to clouding the tank on startup.
• Removes phosphate and silicate together – one media for both of the nutrients that feed nuisance algae and diatoms.
• Fresh and marine safe, at different dose rates.

Freshwater volumes treated are roughly double the saltwater figures above, since PhosNet is dosed lighter in freshwater. The litres above use the saltwater dose, the more conservative of the two.

• Suitable for: reef and FOWLR marine tanks, planted and community freshwater tanks, and heavier phosphate loads where a higher-capacity media means fewer reactor refills.
• Not suitable for: as a substitute for regular water changes or nutrient export via protein skimming – it treats the symptom, not the source of high nutrient input.

• Rinse before use to settle any fine dust.
• Position to maximise water flow through the media without letting it tumble – a canister filter, dedicated media chamber, or a filter bag in a high-flow trickle area all work.
• Leave in place for around 4 days, then test phosphate and silicate. Replace once levels stop dropping toward roughly 0.02 mg/L; if they're still falling, leave it running.

No specific handling warnings beyond standard practice for filter media: rinse before use and avoid dosing into a bare-bottom tank where dust could settle on livestock.

• A phosphate and silicate test kit – to confirm exhaustion rather than replacing on a guess.
• A media reactor – GFO performs best under even, tumble-free flow.
• Seachem PhosGuard – the lower-capacity, lower-cost-per-pack alumina alternative where a smaller phosphate load doesn't need PhosNet's extra binding capacity.

Covered by Seachem's standard quality guarantee in addition to your rights under Australian Consumer Law. Standard shipping applies to all pack sizes.

What's the difference between PhosNet and PhosGuard?

Both remove phosphate and silicate, but PhosNet is a synthetic GFO with a higher binding capacity (1.41 mg/g against PhosGuard's 0.87 mg/g), so it clears a heavier phosphate load from a smaller volume of media.

Do I need a reactor for PhosNet?

A reactor gives the most even flow, but a filter bag in a high-flow trickle area or canister chamber also works.

How do I know when to replace it?

Test phosphate and silicate from around day 4 onward. Once readings stop dropping toward about 0.02 mg/L, the media is exhausted.

Is PhosNet safe for a reef tank?

Yes, it's designed for fresh and marine use, including reef systems chasing low phosphate for coral colour.