With LEDs the heat isn't as much of an issue. But I have noticed on some warm days recently that it went 2 degrees above what I have it set for. I guess on those days I can remove the covers. The tank is acrylic and just has three cutouts on top that I can remove (about 5"x12" each), and the rest is totally enclosed. I don't see that much salt buildup. I may want to get a wrasse, and also I have enough evap from the sump that I don't need to make any more RODI than I already do.