The worms are not bad, they are good actually. People spend big money on "clean up crews" for their tanks when they have a free clean up crew already. I wouldn't worry about them as they are a natural part of the reef. the balance of worms V.S. available food is what I would focus on. If a lot of food is hitting the sand, an increase of flow is the remedy. Let the worms eat what's in the sand now, and they should lessen over time.