Phosphate (PO4) is a by product of the biological processes in the aquarium and is also found in many foods at high levels, as well as tap water, hence the need for effective pre-filtration of our source water by way of an RO unit. PO4 can also come from products in and around your home in room deodorizers, lotions, detergents, etc. thus always keep these materials to a minimum around your aquarium. I cant count all the times I personally have tested clients aquariums to find seriously high levels of phosphate, contributed to the use of harsh lotions on the hands and chemicals around the home. PO4 is also believed to be a major contributor in the outbreak of problem algae. In addition, seriously restricts the calcification process in stony corals and clams, even at low levels. NSW levels of Po4 are around 0.005ppm to 0.01ppm. A level of between 0.01ppm and 0.015ppm is an ideal range to target. At extremely low levels, i.e. those below 0.005ppm photosynthesis will be inhibited in corals, and it may cause bleaching in SPS. So it is advised not to 'over-do' Po4 removal by using excessive amounts of phosphate removing medias. Products such as Rowaphos, and Kent phosphate sponge, are good at removing this compound, and levels must be kept below 0.03ppm. But remember to follow the directions of all medias you use. After loading up many medias will leach the material back into the system in effect acting like a dosing system putting it right back into the water. By far the best ways to limit Po4 build-up is with use of a fluidized Rowaphos reactor, a sump containing macro algae, skimmer, and effective fresh water filtration. Phosphate is the reason for some of the biggest donts in the list of dos and donts in the aquarium hobby. Sources: andy hipkiss, john poole, and various other online medias.
