[kwirky]

*sigh* here we go again on the T5 vs. MH

You should have a poll option of "I've had both and think they're both good"

I'd say if you already have MH don't switch, not worth it. If you want to replace your PC or VHO bulbs, whether they're your sole lights or for supplementation, then they're great. Time it though for when you have to replace all your PC bulbs to squeeze a little extra $$ out of your investment. If you're upgrading from PC or VHO though I think T5 and MH are bringing different things to the game. It's like a football team and a hockey team meeting up to play some basketball lol.

MH's are great when lighting SQUARE areas. the latest reflectors are great and make MH's the most efficient I believe when lighting a tank that can be divided up into square areas (ie: 4'x2' = 2 lights. 6'x3' = 2 lights on good reflector)

T5's are great for awkward tanks. For instance a tank 6'x1' would be better off using four 6' long T5 bulbs than 3 MH's.

T5's are much better at reaching all the areas of your tanks. MH's are point sources so you can only really put corals where the rock isn't causing shadows. It's pretty hard to find shadow areas in a tank lit strictly with T5's. This can be a disadvantage too though depending on your rockwork if you have the need to put something in "low light" areas.

efficiency per watt is not important with our current energy prices (here in calgary anyways) because the bulbs need to be changed more often.

MH's can reach deeper. T5's are still flourescent so their efficiency drops past 24" of water or so.

When people say T5's produce "less heat" from my own experience it's not quite true. T5's produce a LOT of light and I found in my tank the light would be converted to heat when it hits the rocks. I had a LOT of heat in my 120g tank lit only with T5's.

Oh and I bleached a lot of coral with T5's. Nothing could be kept in the top 8" of the 24" tall tank without it bleaching. MH's on the other hand, you have the top "corners" of the tank where the coral's still like 16" away from the light bulb making it easier to have corals at the top extremities of the tank.

Sorry it's a long "shpeel" but I think the argument of "t5's vs mh" should be taken neutrally, since they bring different things to the table. And I do NOT believe T5's are a fad, I think they're here to stay, only they won't be "replacing" mh lighting.

I've kept softies and lps in a 120g (48x24x24) tank lit with 8 T5 bulbs (teklight unit). Now I have an sps nano lit with a 14k 150W HQI and PC actinics (that's being upgraded though cuz it's a 2' fixture over a 3' tank). My dream tank is 36x36x24 lit with a single 400W 14k aquatinic mogul MH on a lumenarc reflector. Very efficient watts/gallon I think. One day I'll have a big tank again. One day...