This is an extensive topic which requires research and experimentation to understand. These few tips and bits of information only touch the surface of the topic, but hopefully will stimulate some thought and further research.

1) It is by no means good for either of these to be too high but having an imbalance with one high and the other low is worse. This is because some undesirable forms of bacteria and algae thrive when these components are out of balance.

2) Achieving zero nitrates and phosphates is not desirable in a reef tank. A small amount of each of these is necessary for coral to survive and grow. Ocean water may be close to zero nitrate and phosphate while the coral thrives because the macro and micro food chain is perfect and cannot be fully replicated in the home aquarium.

3) Another undesirable impact of too low nitrates and phosphates is trouble with Dinoflagellates. The often appear suddenly when aquarium water reaches extreme cleanliness which causes many microorganisms to perish for lack of nutrients. Dinoflagellates possess chloroplasts enabling them to synthesize their own food.

4) Some corals rely heavily on photosynthesis to produce their own food and thus need less nutrients from the water, but many corals use zooxanthellae algae in their tissue as a food source. These algae require not only light for photosynthesis, but also nutrients from the water to thrive.

5) So, what is a desirable amount for each of these components. Consensus is somewhere around 5 PPM for nitrate and .03-.05 PPM for phosphate. Feeding your coral becomes more important the lower levels get.

6) Your food choice for fish can be used to adjust the import of one or the other of these elements. Frozen food tends to be higher in nitrates and dry food tends to be higher in phosphates.

7) Both nitrates and phosphates can be increased by your level of fish and coral feeding and the number of livestock in the tank. Coral acts as a filter by consuming these nutrients so they will be depleted quickly in reef tanks loaded with coral. Fish process nitrate and phosphate from food into the water through their waste so the level will be greater in heavily stocked tanks particularly if you are heavily feeding fish, coral, or both.

8) Nitrates and phosphates can be reduced by water changes but only in direct proportion to the percentage of the water changed so other forms of reduction may be needed. Nitrates can be reduced by bacteria and carbon dosing as well as various forms of bio filtration. Phosphates can be reduced using phosphate absorption media in a reactor, liquid products, and bio filtration.

The Quick and Dirty of Phosphates Role in your Reef Aquarium

Why I often recommend the use of liquid phosphate removal products.

If you want your coral to grow fast and be healthy you will need to test and control phosphates.

Optimal phosphate levels are 0.05ppm for LPS and Soft Corals and 0.03 for SPS Corals (not below or above)

Keys to keeping phosphates from getting too high: Do not overfeed; Use high quality filtered water; Run a good protein skimmer; Implement some form of refugium with macroalgae or turf scrubber into your system; Use a granular ferric oxide reactor before phosphates get too high.

Even those who take all the above precautions will often find when they first test phosphates that they are too high. By far the most efficient way to reduce high phosphates is with the use of Liquid Phosphate Removers. These products will give you the precise amount needed to reduce phosphates 1ppm given your aquarium size. This is the maximum recommended daily reduction level so just repeat each day until you reach your desired level.

Once the desired level is reached you may want to begin use of a granular ferric oxide reactor to keep phosphates low longer. Test every couple weeks and when phosphates begin to rise again change your ferric oxide and use liquid phosphate remover.