What would you do? - Tank Lighting Upgrade.
 

I just bought a 4X54W TEK5 Light for my 90 Gallon (4 foot - 24" Deep) FW (in wall) tank.

I'm thinking of converting it to a reef sometime in the fall or new year.

Since it is behind a wall I don't really mind the look of retro-fit lighting so my question is.

If you wanted to have the widest range of possibilities (getting fairly good par at med to lower levels of the tank) would you:

1) Add 2 more T5HO Retro Fit bulbs to the current 4X54 T5HO
2) Add 4 more T5HO Retrofit bulbs to the current 4X54 T5HO
3) Add 2 more 175W MH to supplement the 4X54 T5HO
4) Scrap the 4X54s and get 2X250W MH

Cost should be considered.. wouldn't want to go NUTS over this upgrade...
Cooling isn't an issue because it is in the basement of the house and it potentially could have a 75 gallon sump which is on the basement slab floor which stays cool.

- My head spins with all of the possibilities.

5) keep the 4X54 T5s and add 2X 250W MH

That would be my choice

J

Getting everything to fit over your tank may become an issue. How wide (front to back) is your tank?

I agree. Add 2 x 250w MH and you're good for pretty much any coral. You can then do a nice mix of bulbs on the T5s to get the best colour combination so your corals will really pop. It would also give you the option of from start of day to night: 2 T5s (1hr), 4 T5s (1hr), 250s (8 hrs), 4 T5s (1hr), 2 T5s (1hr). Then you would have a very gradual brightening & dimming of the tank throughout the day.

If you decide to go 175s instead, try out the Iwasakis (but these are expensive bulbs) with high PAR.

Correction* It is a 24" deep tank

18.5" Front to Back

With the Tek5 Light I have on top.. that only leaves me with about 8-9" of space (front to back) for additional lighting. Are there reflectors about that size?

I do like the fact of being able to run the bulbs in different colour combinations as well as doing the gradual daytime lighting thing.

Then I run into the question of .. where would I put the MHs? I can't split up the T5s (unless I destroy the enclosure of the TEK5 light).

Add 2 or 4 more T5 if you can fit them. I have an 8 bulb T5 right now and it is great. And you can mix and match bulbs to tune the colour as you like it.

Adding more T5's to what you got is the only option if you are really attached to that Tek fixture. I recommend the MH and T5 combo, sell the Tek light you have and go with the 250 watters like suggested then add some retro T5's to get the color you want.

How deep is your tank?

I would probably sell the 4 bulb and pick up the 6 or 8 bulb unit just for space reasons.

or retroft a canopy your self with whatever you want...

This what I would recommend also, make sure to get hqi (double ended bulbs) not moguls.