I'm not an expert, but I have read a LOT of these forums. This is a list of items to do.
1. Be patient, algea battles can last a while.
2. Watch how much you're feeding.
3. Do water changes using RO/DI to help get phosphates and nitrates down.
4. Test water conditions regularly for nitrate and phosphate.
5. Test RO/DI filter with TDS meter.
6. Reduce lighting time temporarily.
7. Setup a refuge with some macro algae to help contend with the algae in the DT.
Lastly and most importantly (mentioned again), be patient. Don't kill off the Zoa because of the algea bloom. You can prune though to get the algea away from it as best as possible.