Originally Posted by jesterns2
I believe he means High Output. Not that i`m very experienced but if you`r going reef you will be better off with MH=Metal Halaide lighting even if its in combination with t-5 actinics. I was told without Mh lighting i`d be limited on corals and definetly no clams. I`d ask around, like I said i`m not real experienced but it`s what I have been told on several different occasions. Hope I helped
Right, jesterns2. HO=High output. HO T5s are adequate for many corals, and there are some that choose T5s over MHs. I'd consider, if you are keeping corals, a 4-bulb HO T5 to be the minimum... especially if it's a tank that is deeper than average. MH would be your choice to get light penetration down near the bottom of the tank.
I'm by no means a lighting expert, but I've recently been researching the same thing as my single bulb flourescent has got to go, and I want to plan ahead for some corals down the road.