Hi Evil,

I'm looking for your expert advice. I currently have a 50 breeder (36x18x18 inch) mixed reef running 3 39watt T5HO bulbs (all ATI; 2 blue plus and 1 special) and would like to convert to LED lighting. I would also like to be able to take this array, replicate it and use the two to light a 90 gallon (48x18x24 inch) in the future.

I'm thinking 4 rows with 12 Cree LEDs each will work on the 50. But am not sure if I can get a happy-medium with heatsink size and LED spacing. Then throw in the confounding factor of optics and I'm really stuck. I want to be sure that I'll end up with an array that has good coverage and PAR on a heatsink that is not too small for the 36" 50 gallon and not too big to put two of them on a 48" 90 gallon. Please help me plan this out so I can start saving $ and get off the T5HO bulb replacement train.

If it helps I plan to get barebones kits from nanotuners.com with ELN60-48D driver substitutions (though these drivers don't appear to be on nanotuners at the moment...?). I'll probably go with a heatsinkusa heat sink (but am intrigued by the use of Aluminum C-channel that I'm seeing on other forums and would appreciate your opinion on this option).

I'm also thinking about adding LED rows slowly as I remove T5HO bulbs... what are your thoughts on this?

I'm sure I'll have plenty more questions as I plan and construct this.

Thanks,
Tom