I have a juvenile in a 30 gallon reef for now (90 gallon coming in July). Definately can cause some water quality issues by the mere fact they eat and crap so much (mostly at the same time) but I find that clipping an algae sheet and one feeding per day or two very small feedings works well for the fish and my tanks water quality (as opposed to multiple daily feedings). I tried the several feedings a day with formula two, one, frozen foods and algae clips for a while but water quality went to hell (by reef tank standards anyway) and the fish actually looked too fat if thats possible (like his guts were goinng to pop and too wide for a tang). I've only had him about 2 months and I swear he has grown some already. In a day however much algae you clip wont be there the next day but he seems to be doing very well as far as acting and showing signs of stress. I'm only keeping two fish in the tank now (tang and royal gramma). Later today I'll be throwing up some pics in the photography section since I reaquascaped and did some much overdue tank maintanence. He's the only reason I'm buying a 90 gallon.
I dont like the buy it just to take it back practice. I cant do that with fish I've had for any reasonable amount of time.
bad pic for size reference