If phosphate is present in too high a concentration there may be an increase in growth of undesirable algae and if the phosphate level is higher than 0.04 mg/L the growth rate of corals and calcareous algae may decrease by as much as 90%.Washing fish food (a rich source of phosphates) after thawing can significantly reduce the input of phosphate, and using a high grade, phosphate free activated carbon can also help to keep phosphate levels as low as possible.The Salifert Phosphate test kit detects, in less than 5 seconds, the level of phosphate present.There are two different ranges within the kit: a low range for phosphate-phosphor from 0.01 - 1 mg/L and a medium range for phosphate-phosphor from 0.02 - 2 mg/L.Sufficient for 60 tests.Can be used for marine, fresh and garden pond water