We've all heard of the three most dreaded compounds in the home Aquarium: Ammonia, Nitrite and Nitrate. It seems Phosphate is quite often overlooked when setting up and maintaining a home aquarium. My personal opinion, is that Phosphate (PO4) is MORE important than Nitrates.
Why? Any amount of Phosphate in your tanks water, will prevent the calcification of a coral's skeleton. What's that mean? Your LPS and SPS won't grow! One study showed that even trace amounts of Phosphates, are able to inhibit growth in certain species of corals by up to 50%. High Phosphate levels have also been linked to the browning out of all SPS species, and the growths of nuisances algaes.
A Phosphate content of 0.05ppm (or less) is considered 'ideal'. The lower you go, the better.
Ever wonder why your precious coral won't grow? Likely because you have phosphates!
But what can we do about it?
Unfortunately for the hobbyist, Phosphates are everywhere. In our water, in our salt mix, in our live rock, our sand, the foods we feed and even in our corals photosynthesis cells.
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Why? Any amount of Phosphate in your tanks water, will prevent the calcification of a coral's skeleton. What's that mean? Your LPS and SPS won't grow! One study showed that even trace amounts of Phosphates, are able to inhibit growth in certain species of corals by up to 50%. High Phosphate levels have also been linked to the browning out of all SPS species, and the growths of nuisances algaes.
A Phosphate content of 0.05ppm (or less) is considered 'ideal'. The lower you go, the better.
Ever wonder why your precious coral won't grow? Likely because you have phosphates!
But what can we do about it?
Unfortunately for the hobbyist, Phosphates are everywhere. In our water, in our salt mix, in our live rock, our sand, the foods we feed and even in our corals photosynthesis cells.
- Use RO-DI water with fresh DI resins. Phosphate (PO4) is an Ionic Compund that is easily filtered out with DI resin. Color changing DI is the easiest way to keep check of your DI. It is also handy to keep a TDS meter on hand. Anything above 2-3 is time for a DI change.
- ALL salts have Phosphates! Test various salt mixes for Phosphate content, and stick to the one with the lowest content. It is easy to dose Calcium, Magnesium or Alkalinity to bring a salt to spec. But it's hard to remove Phosphate.
- Employ a Macroalgae in your refugium. Algaes LOVE phosphates, and will reduce the total Phosphate content within your aquarium water. Prune as needed.
- Running "GFO" or Granulated Ferric Oxide (Fe2O3) will also help eliminate free Phosphate. When used in a media reactor, Ferric Oxide reacts with Phosphate to produce FePO3 or Ferric Orthophosphate by absorbtion [1]. In this form, phosphate is no longer able to react within the coral to inhibit calcification or cause browning. It is advised to stay away from Aluminum Oxide binders as it has proven to irritate certain corals. [2] Anecdotal evidence may also show Ferric Oxide can play a role in irritating corals.
- Run a Skimmer. The skimmer can pull out organic solids before they are able to breakdown and release phosphates into the water.
- Rinse your foods! Foods are phosphate factories. Rinsing the food in a net and RO water will get rid of any liquid it was packaged in. This will help eliminate empty phosphates from entering your tank.
- Feed Smarter. Don't dump an entire cup of food into your tank at once. Slowly add it a little at a time. This will allow your fish to consume the food, instead of getting blown behind your rocks or into the sump where it will rot. Pellet and Flake food has exponentially higher amounts of phosphates than frozen (or even live) foods. Use pellets sparingly.
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