I was looking at a DIY option about a month ago but it would have required me making some type of canopy. It would have included 2 x Hamilton aruba sun T5's and a 48" ReefBreeders LED for about $1K But I really wanted to stay open top and was looking for something more sleek.
Thanks again for all your feedback.
I'm not sre what size tank we are talking here ut from your sketch I'm guessing it is 6' or longer and at least 18" deep.
Since yor talking a DIY build with LED's and T-5's this is what I would do.
For the T-5's I would go with a simple Pair of the 80 watt bulbs down the center of the tank. Then use 2" wide by 1" tall channeling to mount your DIY LED's. If you have a 72" long tank you can mount 18 LED's on each channel.
Running a pair of 1" X 1" channeling front to back you can bolt the LED channels to the as well a sit the T-5 lights directly on them.
I would set up two of LED Channels using 5 Watt LED's in a ratio of 6 Neutral Whites to 12 Royal Blues. This would give you up to 82 Watts of LED lighting per channel that is equivelent to roughly 2 of your 80 watt T-5 bulbs. Cost per Channel would be in the rang of $150.00 each.
You could also go with a third Ral for a pre dawn to post dusk lighting in which I would run 6 True Blue, 6 UV, and 6 Royal Blue LED's running on a 700ma driver. This would give you about 36 additional watts additional deep blue LED lighting to give you a period of time with unbelievable florescense from your corals.
If your tank is wider than 18" from front to backI would add additional Rails like the first two on a ratio of one per each additional 6" of tank width.
You can put all the Blue LED's on a fixed driver of 1400ma but for your white LED' I would use dimmable drivers to allow you to adjust the color of the tank to your viewing prleasure. On the T-5's I would simply use ATI Blue Plus bulbs.
Your biggest variiable to cost would be which T-5 fixture you got. But roughly were looking at an 18" tank $450, 24" tank $600, a 30" tank $750 plus the cost of the T-5's.
If you go with comwercial LED fixtures I would go with two smaller LED units ratyher than one big one. This will allow them to sit closer to the edges of the tank.