Seachem Phosguard

If you run a reef tank, chances are that you will also run into phosphates.

Phosphate (PO4) is a compound of phosphorus and is an essential trace element in saltwater. It is a nutrient source for corals and algae, a building block for living matter and is present in every reef tank. Phosphate can be introduced into the aquarium from multiple sources: tap water, fish food, and supplements, for example.  Very low PO4 can cause pale corals, and too much will cause browning.

Finding that sweet spot is key!

If you suspect phosphates, the first step is to get a test kit and determine your level. Often times, doing water changes and cutting back on feeding will lower nutrient levels. However, if this has not changed your phosphate level, then you might consider using a phosphate removal media, such as PhosGuard.

PhosGuard is a high capacity and high efficiency filtration product, made by Seachem. It is designed for the removal of both phosphates and silicates from marine or fresh water aquaria. Silicates causes an unsightly brown and tan appearance on surfaces in the aquarium, especially rocks, sand and the glass.



Bead-shaped for optimum flow characteristics, PhosGuard rapidly removes phosphate and silicate and has an exceptional porosity for enhanced capacity.

You can use PhosGuard two ways: Passively in a media bag in the sump or back chambers or in a reactor.

When using any phosphate control media, using less is better than using more. Removing phosphates rapidly can shock the system and cause sensitive corals like SPS to lose flesh. As with anything reef-related, slow is the way to go.

For tips on how to control phosphate in a reef aquarium, check out this article and the accompanying video to learn more.

If you've tried PhosGuard and/or have experience battling high phosphate levels and would like to share your experience, please leave us a comment below!