Lighting Decisions

Im at a crossroads and need help with this decision. So I'm def gonna upgrade my lighting after Xmas and can't decide between three 175w or three 250w MH. The thing is my tank is fairly shallow, like 18" from the surface to the sandbed, so 175w sounds good right? BUT they will be in a closed canopy about 13" above the water so maybe 250w is needed (not an expert). And the final factor is the heat issue. Will there be a huge difference between the two wattages I really am trying to avoid the need for a chiller. I plan on placing four fans two blowing over the water surface and two blowing out the back of the canopy. I also plan on running T5 HO Acnitics, probably these Nova 36" fixtures I found. They are 2x39w each would I need two or four? And should the T5's be closer to the water or the same as the halides? I know these are alot of questions but thats why I need you guys to help. Thanks everyone

 

The 175w will do the trick for what your Sig lists as livestock, if you have any desire to go the sps route the 250w will serve your needs better. personally I would go with the 250's, why spend the money to upgrade twice if you dont have to.
you wont need the t5's unless your trying to tweak the color of the tank lights, or trying to do something with simulated light cycles before and after the halides come on. the fans sound like they will do the trick, I would try to find a way to vent out the top of the canopy if possible.

 

Well the whole reason for the upgrade is to go the sps route the softies were kind of a training ground this is my first saltwater tank. Ive even thought about one 250 in the middle and 175's on the outsides or vise versa

 

Thats what I thought you might be planning... go with the 250's.
It wont come with the greatest bulbs, but they will work fine for the first 8 months or so and then you can upgrade the bulbs as you replace them.

 

ok thats the way Ive been leaning anyway. Could a 250 ballast run a 175 bulb or would it blow up?