Lighting advice for an inherited tank

[Robcarl]

I just inherited a 90 gal, 48" tank. It has rock but wouldn't call it a reef tank just yet. Came with a pair of Clowns and a yellow tang. Tankmates includes three urchins, the largest hermit crab I've ever seen (2-3"), a reddish shrimp of some sort (not overly shy so apparently not a peppermint) and some snails and small hermits. The urchins seem to be losing spikes and I would suspect the large crab. Tank is over ten years old.

The previous owner had a 175 MH which now doesn't work...don't know if problem is ballast or bulb. Apparently, the light's been out for two + months already. Reportedly he never had much luck with anemones or clams. From my reading, perhaps insufficient light?

I was advised by an online fish store to get a single 150/175 MH however if I want to put some inverts in the tank will this be enough?

Can I retrofit the existing MH? It looks quite old. If so, and I need more wattage, can I go for a dual ballast and run it and a new MH with it?

I also came across a 48" canopy by Hamilton Technology that has 2 250w MH and 2 96w actinics, includes bulbs and ballast for $625. According to my reading this would probably cover all my future needs. Any experience with this manufacturer? They seem to be cheaper than some others (such as Maritime) but I don't know why!

I don't want to say money is no object but I'll find a way to do what it takes to make sure my options for adding tankmates in the future aren't limited.

Right now I'm awash with information and could use advice to sort through it all. Thx for the help!

 

[electrikat]

Suggested mh use is one bulb for every two feet of tank length. I also have a 48" 90g tank and we have two 250w mh with two no 40w blue actinics. That's 7.25 wpg and will support any animal we want including clams. Hamilton is purported to be one of the leading manufacturers in marine lighting. The crab is going to be a problem. Most hermit crabs like you see at the beach are not reef safe because they get so big and will eat your fish. I lost two angels and several small fish before I figured that one out. You will need blue leg and/or red leg hermits to keep the tank clean without them eating your other animals/corals/snails/etc. Good luck with it and I think you will be very pleased with the results. Research is key and be prepared to exercise a lot of patience.