Get an FR for the purephos, do water changes with clean source water (RODI or Distilled) and a good quality salt, replace activated carbon if you are using it, if not, use activated carbon. Make sure your skimmer is operating properly and set it to wet skim as much as possible. Try to manually remove the algae as much as possible. Maybe you can try getting mexican turbo snails to help with the general algae cleanup as they are excellent as cleanup crew. HTH