2 x 250 or 1 x 400 mh and specific sand for deep sand bed?

[pugmommie]

I am setting up a 120 gal tank 48x24x24. I plan on having a mixed reef lps, sps, leathers, zoa's, and different clams.

I already have 2 of the Hagen Glo T5-HO 2x54w for the hood.

I have 2 spider light reflectors for the mh, but I have not purchased the ballasts or bulbs yet.
I was planning on getting 2 250 w 14,000k bulbs and going with eletronic ballasts.

I have heard different opinions for the mh. One lfs said not to put 20,000k mh in tank cause it was hard to look at.
Another lfs said to use 1 400w 20,000 k because it would take care of algae problems and that a magnetic ballast would last longer and that using 2 250w would be a waste. That the 250w would not penetrate to the bottom as good as the 400w.


Is a 400w really necessary?

I like the 2 x 250 mh because I can have the light spread out more and I thought it would still be plenty of light for the clams.

I have a hood that the lights will be attached too. It is about a foot tall.

Just trying to figure out what to do and get the right ballasts and blubs.

What are your recommendations?

I have also ordered 4 x 40lbs bags of ocean direct caribbean live sand, I'm not sure exactly how deep this will make the sand bed but I thought it would be a good start. I figured even if it wasn't too deep it would serve the purpose of sand sifters I might put in tank.
Well when I told the lfs guy(the one who said to go with the 1x 400w) he wanted to know what kind of sand because their is specific sand for dsb and I have no idea if what I ordered was for this purpose or not. He kind of confused me. He said if I don't have the sand depth correct and right kind or sand I will have bad nitrate problems.

What do you guys think?

[Konadog]

I think you will like the coverage of two bulbs "vs" a single bulb better. If you only use one, you will limit yourself for placing your corals. I ran 2 250w bulbs on a 24" deep tank just fine.

An easy way to visualize how deep the sand up purchased will make your sand bed, just lay the bags on there side and measure the coverage and how deep the sand is in the bag, this should give you a rough idea.

[cloakerpoked]

Sounds to me like the guy is just trying to sucker you into buying equipment and sand you don't need. I keep a 4-6" DSB with mostly rinsed sterilized play sand from Lowes and a very shallow (1" or less) top layer of actual reef sand. The tank has been set up for about 2 years now and has never had a Nitrate problem. To be fair, I do keep a very low bio-load (about 6 fish currently in 200 gallons of water) but still.

My tank is a 120 (same size you described) and I run 2x250 MH 12k (going to 14k as soon as my new bulbs get here) with 2x110 VHO actinic suplimentation. I keep a mixed reef, and have a 5" Crocea clam on the substrate and a pink birdsnest coral on the bottom of the tank and both seem to be doing well (they've been there for about a month now. All the SPS grow great, as do all the softies and the few LPS corals I have. I very much prefer the coverage of the 2 bulbs, and cannot for the life of me understand why you'd want only 1 bulb in a tank that's 4' long.

Its probably its own thread, and I haven't read too much up on it, so don't take this as gospel, but I read somebody (can't remember who now) who did PAR readings (basically light intensity measurements) in their tank with different types of ballasts and bulbs and it seemed to me that he got higher intensity output from the e ballasts than the m ballasts. Either way, 250 watts will be more than enough for you, especially if you keep most of your SPS and higher light demand corals a little higher in your tank.
http://i364.photobucket.com/albums/oo85/cloakerpoked/IMG_1392.jpg
http://i364.photobucket.com/albums/oo85/cloakerpoked/IMG_1391.jpg
Sorry if the picture quality is a little less than I'd like it to be, but this should give you some idea of the way my tank is set up. If you have any other specific questions, feel free to PM me or whatever.
Hope it helps!
Nate

[pugmommie]

Thanks guys, that makes me feel better.

cloakerpoked - your tank looks pretty darn good to me!!

I going to go with the 2x250 w mh.