GFO (Granular Ferric Oxide) ran in a reactor (Two Little Fishies or Bulk Reef Supply) is a good way to reduce/control phophates. However, I have used Blue Life Red Slime Control in the past with great results. You just have to follow the directions exactly.
In my experience, lack of flow/dead zones are a big factor when dealing with cyano. You just want to make sure any uneaten food or deritus is kept suspended in the water column and pushed towards your overflow so it can be removed via filtration.
I like sand sifting livestock such as Super Tongan Nassarius snails and Tiger Tail Cucumbers to help keep the sand clean as well.