No longer up in the air

I checked and IIRC it came out about $65 to $100 less, but that didn't include hardware to hang it and such. Still should be a bit cheaper though.

 

I hear you on overkill M24 but honestly one 250w was perfect for what I wanted. It's nice knowing I can grow anything I want if I do decide to get a lot more SPS. One of those things, there is no such thing as too much light for a reef .

sj if you do go T5 I would def suggest a combo of ATI bulbs to get your best out of whatever fixture you choose.

What are you looking to keep in the cube? Even though when I started reefing I was like "oh I'll just save and get a decent light, I'll just get some softies and easy LPS.." But then you get the bug and you want more light demanding coral, clams, anemones, etc, so start strong in case.

 

Ok. I couldn't find the pieces that M2434 talks about but I did find Lumatek 250W Double Ended HQI Metal Halide Retro Kit. $230 with including a 250 w bulb, select-a-watt ballast and the proper plugs w/15ft cord. I'm also going to do the 45 cube sump. I've never seen a cube configured for a sump/refugium before. Suggestions?

 

Don't I need the light for the cycle?

 

I doubt many people have cube sumps, so, you may have to use some improvising. It looks like there are some on the web, if you search. Here are two I just found with a quick search:

RR Hex and Sump!

Help with cube sump - Marine Aquariums of South Africa

And you don't need a light to cycle, cycling is really for bacteria, not algae. After the bacteria is established, then you can bring the light online. You will probably get an algae bloom for a week or more then, but this is natural.

Mojo, you can have too much light. If you've taken a biology class, you've probably heard of photosystem I and photosystem II in plants and algae? Zoox has both and as it turns out, PSII is very prone to light damage, so, if the light is too intense, the algae actually "inhibits" its function, this is called photoinhibition.

Dan Riddle did some tests and found that this point was actually pretty low, even for some corals that tend to be thought of as light-loving
Feature Article: How Much Light?! Analyses of Selected Shallow Water Invertebrates' Light Requirements — Advanced Aquarist's Online Magazine

For this reason, in nature, a lot of corals in shallow reefs, are most productive during time periods other than high noon. At noon, near the equator, the sun is of course very bright, however, the zoox in corals "tolerate" this, by shutting down PSII. They don't necessarily "thrive" in this environment. (Also, there is issues with generation of oxygen radicals, but that is another can of worms).

The PAR numbers Dan found are certainly withing reach of a 250W MH and definitely 400W for many corals. These were shallow water corals though, other deeper water corals can be more sensitive. I think a 250 is OK though, but you could get photo inhibition if you put more sensitive corals near the top for example. I don't mean to say there isn't a benefit to more light for many corals though, but like everything there is such thing as excess. You just have to design your tank, to your goals.