+1

I ran one of the cheaper 4 bulb units over my 90g. Great for soft corals but not enough for sps. A pair of 250w halides I put over the same tank was no comparison for the sps corals. Like night and day and the corals showed the difference.

Now the high end t-5 fixtures may a different story but never owned one. If you like the t-5 look, then I like the idea of adding another 2 or 4 bulb fixture. Guess it depends on how many bulbs one wants to replace every year and the corals you wish to keep.

I've been doing this light thing (for FW High Tech planted) for a while and never really thought about this. Great point.

What type of corals do you see yourself keeping? LPS, zoas/palys, SPS, mixed reef?

If you go with 400W halides you never need to worry about "upgrading" again, and can keep any coral you like in terms of light. 2x250W would also work with florescent lights for actinic/dusk-dawn effect. I personally use single ended bulbs, lots of selection in terms of light spectrum and cost.

I actually have a 1X400W setup sitting around.. but I am a little concerned about heat with that light (especially a pair of these lights). I have a little bit of a vertical limitation and the light would be about 3"-4" off the water.

If I ran 2X250s.... couldn't I put SPS (eventually) half way up? I realize that coverage to the bottom wouldn't be great...

Keeping 400's that close to the water could be a concern, when most people put their tank in a wall they usually have a little more hight to work with (as everything is hidden). 250's would also present a similar challenge, although not as bad as the 400W's.

You could indded keep SPS half way up and higher with the 2 x 250W, but should the SPS bug hit (which has been known to happen!), well many people want to upgrade to the 400's.

I agree with the recommendation to go with an additional 2x250 or 175w MHs. I would advise against the 400s based on a) power consumption, b) increased evaporation, c) the oops I burned myself again factor.

I used to have 3x 400w over a 30" deep tank, and I didn't mind it then, but it was on the cusp of being too much for the tank. I loved 175w over 18" deep though, it worked amazingly well for me.

Check out Sanjay Joshi's website for more details on ballasts, bulbs, PAR, etc. Its a good place to start if you are sure you want to go with metal halide.

The cheapest route would be to try and squeeze and few T5s in with the teklight, but going all out with 250W MH with retrofit T5s for actinics is the best long term keep anything you want solution.

I second checking out Joshi's results. Careful selection of bulb/ballast along with good reflectors can save you a lot of electricity and heat while still giving you very good PAR.

don't mean to hijack the thread, but i have a 24" deep tank and i am planning on running 1 X 250 MH HQI + 2 X 65w PC's, will that be sufficient for SPS and (hopefully) calms? total tank size is 24" wide X 24" tall X 18" deep (front to back)

I would say definitely that would be fine for sps most any place in the tank.