175W enough for SPS?
 

Alright I'm stuck. Again :lol:

Is a 175W MH gonna be enough to have SPS?

The tank is only a 20 tall, and I'd rather not have a more powerful light than I need, since I do plan on running them for 8 hours a day. But if I get the 30 tall which has the same dimensions but longer, I might want something more powerful... any thoughts would be helpful.

Hmm I should have put this into a different spot, it should probably have gone into the equipment forum.

Yes you can grow most sps under 175 watt MH but many of them will need to be placed fairly high up to get good colour.

Iwasaki 14K (sometimes called 15K) 175 watt MH with an electronic ballast has been tested to have the most PAR of the 175 watt bulbs.

Cheers,
Vic

I used 175w for the first year of SPS keeping. They'll live, and grow a bit, but not the same as you'd get with bigger bulbs. Especially if you go deeper, you'll want at least 250w.

The 175 watt Iwasaki with an electronic ballast is supposed to have as much PAR as any 250 watt bulb according to Sanjay Joshi.

It's a pricey bulb though.

Cheers,
Vic

If you do the 20" deep tank, you could go with HOT5s, 6+ bulbs would do nicely. Just thought Id give you a bit more to think about.:biggrin:

Well, the plan is to have 2 T5HO bulbs running 12 hours a day above the tank anyhow. This was more because of colour considerations more than anything, I want to use a 10K bulb because I like the really bright white sunlight effect. I was planning on using a XM 10K bulb with a PFO electronic ballast run 8 hours a day, and and 2 actinic or 50/50, maybe a Fiji Purple T5HO on for 12...

Does this change the equation at all?

OH, and the tank is like 15 inches deep, part of the tank will have a 3" sandbed (the seagrass part)....

I used to be using 150wt MH, at a depth of 21in, and have switched to t5's. with the t5's at the same depth, i have experienced much more growth, and color in my SPS.

Hmm...

Well, the reason I'm going with MH to begin with is for the shimmer, I really like the effect and I think with the surge I will get some interesting caustics. The other option is to find a 70W MH to use as an accessory light, to provide that shimmer, and use 6 T5HO bulbs. Unfortunately, I've searched and searched for 70W MHs and they are impossible to find, so that idea is out... unless I call these guys http://www.venturelighting.com/NAindex.html. They have MH ballasts down to 50W, though I've never EVER seen a 50W MH bulb.

It all comes down to one thing... I need a wider tank :lol:

Hmm, a couple questions... what kind of bulbs were you using when you ran MH? How many T5s are you running now, at what wattage, with which bulbs?

I think if I remember he's running...okay I cant remember(I want to say 12 for some reason, but my brain is trying to recover from last night...) It's a big light unit though and the colour on his SPS are rediculous.

That's not surprising... 150W is pretty weak for a 21" depth..

How about 175 over 15" J? I guess what I'm asking here is will I get good growth and colour from 2 T5HOs (though they'll be 60/40 actinic and a Fiji Purple) and a 10K XM with a PFO electronic ballast?

At least, this is tentatively what I've decided I want...:lol: It'll probably all change, who knows maybe I'll go with all T5HO in the end... that's like 200 W of T5 over a 24" long tank, if I go with 8 bulbs and I end up using the 20 gallon after all, making it 25 W less than the proposed metal halide and fluorescent combo. I'm not sure if that translates to 25 W less light, or less power consumed though...

Are you sure its a 20G tall?? I thought a 20G regular was 24x12x16...

Anyways, I had a 175W MH over my 20G (regular) and I had great Monti growth, as well as good growth on digitata, birdsnest... never kept the tank long enough for acroporas...

I doubt you will fit 8 bulbs over a 20G... 8 bulbs generally spreads to 24x24.. You'd be hard pressed to fit a 6 bulb unit over it.. :)

Yes, a 175w MH will be ample on a 20 gal. aquarium. Your SPS will be fine at different levels of the aquarium. The Iwasaki was a good recommendation.:wink:

Indeed, upon further reading the Iwasaki bulb is very white when run with a good electronic ballast. So that's what I'm going with :biggrin:

Yup you're right, each reflector for a T5 is about 2.5 inches wide, but I can totally fit a MH and 2 T5s over my tank. This would also work if I get that 30 gallon :wink: Though one end would be slightly darker.

On a side note, you're more than likely right about the way I labelled this tank... it probably is just a normal 20G, but most of the other 20s I've seen in the past (not many) were longer and only 12" deep.