Hmm....ambitious plan, but you need to know how difficult H.magnifica anemones are to keep. They are considered a most demanding and delicate anemone and really only very experianced aquarists should try to keep them. That being said, these anemones require lots of light, lots of water movement, and excellent water quality. here are some links for you to read over....
HOST ANEMONES by Joyce Wilkerson, PE
Anemone FAQ (PDF)
The Breeder's Registry 2003 Anemone Survey
FIELD GUIDE TO ANEMONE FISHES AND THEIR HOST SEA ANEMONES
Keeping Anemones by Rob Toonen
Anemones in Captive Systems pt 1 by Robert Fenner
Anemones in Captive Systems pt 2 by Robert Fenner
You'll also find lots of other links in those last two by Robert Fenner.
Are you committed to the idea of an H.magnifica or do other anemones appeal to you also?
So lets start breaking down what you have here....
I'm in the process of setting up a 30 inchx30x30 acrylic cube. The theme is ritteri anemones and a small school of clownfish. There will of course be a an assortment of sps and softies. The idea is to have no leaks (therefore no sump).
I have a sump and havent had any leaks at all. Its all in the planning. Mine is set up so if power goes out, the tank backsiphons only so much water and wont overflow the sump. This is easy to do, I'll explain later if you want. Your tank will be approximately 115 gallons overall, but you will have a fair amount of this water going verticle so you wont have as much room as it sounds. Also keep in mind that H. magnifica reaches 36+ inches in overall size, so technically, your tank is already too small for a full grown anemone, much less any corals you want to add.
Lighting: 175 watt DE metal halide (10k) with at least 4, 2 feet 75 watt vho uri actinics in a custom hanging height adjustable canopy. Any ideas on the halide bulb brand or kelvin?? I only have experience with vho's, any opinions on T5's
To my knowledge, 175 watt DE's dont exist. There are the 150 HQI's, (not necessarily DE's), 250 watt DE's, and 400 watt DE's. For a 30 inch deep tank housing SPS and a H.magnifica, I woulndt think of going anything less than 250 watt bulbs, DE's if you want to be able to keep light hungry corals near the bottom. From what I've been able to research, T-5's are an adequate replacement for VHO's and they use less energy. However, to be honest, you dont really need actinic supplementation because all the corals and anemones photosynthetic needs are taken care of by the MH lighting...as long as you are running at least the 6500K Iwasaki or higher Kelvin bulb. People are primarily running VHO's/PC's/T-5's in conjunction with MH's for aesthetic reasons.
More reading for you....
Sanjay's reef lighting pages
250 watt SE bulb/ballast test
Circulation: Wave2K (any negative feedback), supplemented with 2 Tunze turbelle streams (any opinions on which one of these to use because they have huge price differences) Can I hook the turbelle streams to a tsunami wavemaker??
I havent been able to find anything good said about these things. I would avoid them entirely. A better choice IMO, for this size tank, and for what you are wanting to do is
www.oceansmotions.com . I have a 4way HD unit for my 58 gallon tank, and I'm happy with it. If I had a larger tank, I'd probably go with a motorized ball valve, but since one wont fit in the area behind my tank, I went with this instead. Evolution Aquatics is correct when he says your tank is too small for Tunze streams, although I feel they work fine in tanks 4 feet or longer, and dont really reach their full flow potential in a tank smaller than 4 feet. Check out this thread for some pointers on water flow for your tank...
The Plumbing and Water flow Workshop
Filtration: CPR dual bak pak hang on the back protein skimmer rated for 120 gallon aquariums with dual skimmer boxes (want to avoid anemone soup).
I'm not a big fan of the CPR skimmers. They work, but not well enough to do the job for a H.magnifica tank. I would suggest you buy the best skimmer you can afford.
More reading for you....
Skimming 101
If your good at DIY, check this out...
DIY Skimmer Workshop
I also saw that Evolution Aquatics has some very good skimmers for sale at his website...might want to look there too...
Bottom line, a skimmer is just as important as Lighting and Waterflow to this type of tank, both the SPS and the Anemone will require excellent water quality to do well.
I'm also thinking about hanging a large CPR refugium on the back for mangroves(really need opinions on that one!!).
If you design a sump right, you could easily have your refugium in there, would save you some space, and make things easier to access. I've never kept mangroves, but from what I've been able to read, the only negative side is they suck up magnesium from the water column. Magnesium has a direct correlation to the calcium and alkalinity levels in your water, so you kinda need to pay attention to that.
Finally, the tank will also house a 16 inch farm raised gigas
Hmmm.....Do you already have the clam? I would suggest you go with a different type of clam as the gigas grow really quickly and will also out grow your tank. I would suggest going with some of the smaller clam species...T.maxima, T.Crocea, etc Derasa's are also pretty, and hardy (for a clam) but dont grow as large as the Gigas, but they still grow very large...so keep that in mind....
Hope all of this helps, I realize it sorta looks like I'm ripping up your tank plans here, but I'm not. I'm just trying to give you some other viewpoints and some info you might not have had. You seem to have done some research and are really researching this before you commit, which is great. Researching and reading will save tons of money and aggravation in the long run.
Nick