it also depends alot on the fish that you are wanting to keep. some fish need the full length size 125 (6' Long) for swiming. such as alot of tangs. so decide what you gonna be keeping then go from there. i think the tall and deep tanks make better reefs. easier to aquascape and just look...
very sorry to hear about this. luckly i havent had a powerhead so burn up. i had one starting to make noises so i took it out. hope your corals make it.
one of my lfs will do the same. they have a panther grouper thats maybe 1.5" and want $40. there is another store with one like 8" for $50. i dont understand it sometimes. my next order will be from here also. when ever it comes in.
try a fresh water dip. but keep a close eye on him. this may fix the problem for a few days untill you can treat him properly. if hs is in your display then the ich will probably spread.
i would say that he will probably eat one from time to time. especially at night. most eels are nocturnal. so you will probably wake up with some missing. you may oculd keep him well fed and him not do it. its a 50/50.
many many choices. a large lion, panther grouper, zebra moray, emperor angel, golden puffer, porcupine ouffer, lunare wrasse, and any trigger. that would be my list.