Color rendering index the higher the CRI the closer to natural color

GE makes 6000k colour temperature 20W's. They're usually about $10USD in american stores, better than the $20-30 each i've seen the coralife ones for sale here.

I'm also thinking just forking out the money for a teklight retro kit would be worth it. Go 2 bulbs over a 48"Lx10"Hx12"W tank. Would be enough for most things, and I could get another one later. I know it'd be higher quality than the dairy-queen bulbs and more reliable. And more versatile in case I decide on doing something else with the lights later. Those workhorse ballasts are pretty universal.

It'd be about $190 with bulbs if I went T5. Better than $15-20 each for the dairy queen ones, and probably needing at least 5 bulbs. That's at least $100 there for the cheap ones, not including sockets and wiring.

I think 2 bulbs over a 12" wide water surface would be fine in an 8" tank with a water depth of like 7.5"

It's funny. I've got 2 reef tanks going now. Only ~5 days after the 2nd one's running, and I'm already planning on another. I'm going end up with a fishroom before everyone else in the house realizes it's too late :D

Sorry to hijack but what bulb, other than metal halide, could be used to grow sps if they're close to the top? I'm setting up a 24 by 24 by 18" deep refugium that will be divided in to two sections: one section for macro and the other section for sps frags. Right now I've got a Coralife 150W clip-on pendant but I would prefer to use that on a 33G LPS/Softie tank that I'm setting up. Thanks, and sorry to hijack again.

I just got my first sps in my 120g, and it's lit with a 48x24" 8 bulb teklight unit (~420W total). The coral's grown about 1/2" on each of it's branches in the 15 days I've owned it so far. The lights are about 10" from the water surface, and the coral's about 9" below the water.

That's why I'm thinking T5 would be a great choice for a grow-out propagation tank for it's efficiency.

Any ideas on how to design a rack-style multi-tank stand for tanks 48"x14"x12"? I'm thinking of it holding 3, maybe 4 tanks, that will be added in increments as they're needed, with only one tank initially. Building materials would probably be 2x4's and plywood.

Or any ideas on the cost to have a shop build a tubular steel stand like this?

If I bought an icecap 660 ballast, I could start with one of these tanks, then add tanks and bulbs as needed when I feel the need to expand.

HD sells a 2 pack of 23W 6500K (daylight) bulbs for 14$. i use them in my terrariums.

thanks for the help. I'm thinking I'll go with a T5 setup instead. Now I'm debating what kind of setup would be the best for the lowest cost in the long run. Either of the two:

two 4' teklight retrofits (4 bulbs in total, 2 ballasts) over the one tank, then buying the same all over again for each tank I add until I have 4 tanks in total.

Or 4 icecap reflectors and endcaps, and a single icecap 660 ballast. higher cost up front, but expandable in the long run...