Lighting a 90g

I am planning on upgrading from my current 40 breeder to a 90g reef ready tank. The plan that I have in mind for the 90g is to create a large "mountain" or outcropping in the center on the tank. I want the tank to be mostly SPS corals with a few LPS from my current tank around the bottom of the mountain. the majority of corals would be plating montis and tabulating acros but I would also like some branching SPS on the upper portions of the rock work. My question is, since all of my corals will be concentrated in one location in the tank, and there is no reason to light the open swimming areas, do you think it would be possible to provide enough light with just a single 250w metal halide? I have attached a plan I drew of the tank to better illustrate what I would like the aquascape to look like.

 

Are you planning on still having some lighting over the rest of the tank, i.e. a couple of T-5 just for light? If so I would think it would work, if not, then IMO it won't do, or at least it won't look right.

 

I got a 48" 4 bulb AquaticLife hoT5 from a friend but I'm worried that this fixture won't provide enough light to a 24" deep tank so I'd rather go with MH. I guess I could run both but a 250w plus 4 hoT5 seems like a lot of light.

 

I wouldn't say that is "a lot" of light for a 90. Especially an sps tank. I'm running 300 watts of metal halide lighting and 192 watts of power compact. I have mostly lps as well. It's all about letting the coral get used to the light slowly.

 

Really wouldn't call that to much light for a 90, pretty typical for SPS, might even be a bit lower compared to other setups since most people would use 2 MHs, also having T-5s to supplement a MH is always nice for the color options it gives you.

Do you actually have the 90 gallon tank already? Is it a custom rimless or a typical glass 90 gallon with the black trim including a center brace? I ask because your plan isn't going to work very well with a strip of black plastic bracing going straight over the top of your mountain. In fact with the center brace you might have to do 2 MH anyways.

 

Yes I have the tank already. It's a reef-ready 90g tank with a cross brace and a corner overflow.

 

With that cross brace your single MH in the middle wont work very well. May need to go with 2 of them. Or find a different route...

 

eh. I'm trying to find a way that won't use a ton of power and create so much heat but I want to avoid LEDs

 

I have a 90 gallon too that I'm running strip like LED fixtures on and even with them covering the entire length of the tank I still have a noticeable shaded area under my brace near the top. You're not going to be able to get away with just having a single MH over the center of the tank with the majority of your coral on a centered mound, even with 2 of them you're probably still going to have some shading at the very tip of the mound.

It sucks but having a central mountain in a tank with a centered brace just doesn't work that well. Personally in my next tank I plan to get a custom job with the bracing made of glass instead of black plastic.

If you really want to stick to that scape I suggest T-5s, try setting the T-5 fixture you have right now on the tank seeing how far down the brace is shading the center.

 

hmmm...the tank is empty and I was going to real it anyway, I wonder if I can remove the cross brace and replace it with acrylic?