Sounds to me like you are overfeeding. I feed every other day once a day. You can feed your Regal Tang some sea veggies if you think you are going to starve her. I also only feed mysis shrimp and ocean plankton (krill). I installed a Phosban reactor on my 120 gallon and found it took a couple of weeks to start working well. A little patience is needed with the Phosban system.
I do 20% water changes every two weeks. At that time I make sure all debris are mixed up and removed from my sump and any algae on the hard to reach areas on the glass are cleaned.
Are you using a sump or a canister filter system?
Also What type of lighting are you using halides or fluorescent?
By the way welcome to canreef
