I know they can be fine for a while, they grow slow. The trick is to move them before they reach the stressful point or risk stunting, plus excess bioload. I have a small pair in my evolve8 currently, but I also have 4 tanks going I can play musical chairs with. How are you liking the colors from that bulb? I have a 20k boostled par30, I loved the glow, but colors morphed and wasn't showing any off my rbta very well. Now I use and absolutely love my full spec par38 from LEDtric. Now I won't use any LEDs that don't have at least three colors, and preferably neutral white instead of cool white (I still wished my LEDtric bulb had neutral)