Red Sea No3Po4-X - Biological Nitrate & Phosphate Reducer Highly effective, reef-safe solution for the long term prevention of algae through precise control of nitrates & phosphates. Controllable and safe nitrate & phosphate reduction. Sets and maintains ongoing desired levels of nitrate and phosphate. Promotes coral growth and coloration. Reef Safe, no undesirable side effects. Easy to use, reliable and cost effective. Red Sea NO3: PO4-X is a unique complex of a number of different carbon molecules and other organic-bonded elements that enable a controlled biological reduction of algae nutrients (nitrate and phosphate) by naturally occurring nutrient reducing bacteria that exist in all aquariums.