Water clarity problem

[waterbear]

As far as I know the only way to deal with high nitrate levels is to dilute (drain and refill). Your undedited post said nitrates, not phosphates. Either one can be a 'limiting factor' in algae blooms. Phospates are treatable. If both are present then treating for phospahtes might not help as the remaining nitrates will supply food for the algae. If there are no nitrates and only phosphates then it might be useful. Phospate treatments are a bit of a pain, however.