i currently have a 55 gallon tank that is 18 inches deep. my roomate and i have recently moved over to the salt water hobby and are very excited with out tank. we really want to build a beautiful reef with many different corals mostly soft but possibly some hard as well as clams, yet the debate on lighting and whats important is very confussing for us because of our limited knowledge on whats important. we are two college students so my question is what is the most cost effective lighting i can get. something that i might be able to upgrade with time but will put me on the right track to starting to purchase some soft corals and start some growth on my liverock?
thanks miguel

Big difference in amount of lighting in keeping soft corals and clams.

Soft corals require the minimum amount of lighting for a reef tank while clams require the maximum.

Many people mistake LPS corals as soft corals.

I will tell you what I did and had some level of success with. I didnt want to buy the regular T5 lights because it was so expensive to get a 5 or 6 light fixture and then the reef bulbs for it were an additional $20-30 at my LFS (over priced and under serviced). I decide on a MH. You might be thinking thats way more expensive! Not so unless you want coral life or some brand name bull...What I purchased was a 400w MH grow light. It came with a new M59 balast, decent reflector, cords, a 6000k bulb, everything you need but the chain to hang it(no assembly required). I have since moved to a 14k bulb to cut down on alge growth, however the corals, hard and soft alike grew like crazy (under 6k they dont get the color but boy do they grow. Several coral propagaters I know use 6k to grow and then 10-20k to color them up before sale) That also may be due to the fact that I have almost 9watts per gallon. I also got the 14k bulbs off ebay for about $20 each, from different sellers...one bulb was great the other was dead within a month. The good seller was, greatdel. The light was purchased for i believe $119 (all new parts) from HTGsupply on ebay. I think they probably supply mostly closet pot growing opperations but I recieved a great light reguardless. From experience keep a spare bulb on hand! I lost like 10 sps frags because I lost my MH light and had nothing else to keep them living...All the LFS wanted $100-150 for a bulb and I couldnt do it at the time. So I ordered off ebay and waited a week...2 of my frags have actually started to come back , i was amazed! Lesson learned, I keep a spare bulb around now. If you go with a MH light dont get a 400w unless you plan on upgrading to a large tank in the future as 400w is far to much for my 46g or your 55. A 250w would probably work just fine...I bleached some frags (which came back till my light died) because I was told they were very light hungry and put them in the top third of the tank, bleaching them white in 2-3 days. I since discovered corals cant be in the top 1/3 of the tank, they did well...I kept several in the sand bed even. The light is obviousy to powerful lol. But I am switching to a 190g all glass and have purchased another 400w MH...good luck

ps. if you get a MH you can grow whatever you want!

we checked it out and that was a great idea. our light is in the mail. we even used the same company. we are really excited to get some neat growth.

awesome! I hope it works out, keep us informed. make sure you keep the light a foot or so off the surface, they put out alot of heat so leaving a gap will cut down on the temp absorbed by the water.

and also, if you need to, you can clip a fan on the rim of the tank to blow cooler air across the water to help control the heat that could be absorbed by the water. i think that you have made a good choice in lighting. with the halides, as mentioned above, you will be able to keep anything you want, anywhere in the tank. the halides leave no area that you can not keep SPS corals at. i run them and have a couple of acropora corals on the sand bed.

I have a fan on my tank, the only down side is it increases the water evaporation...or seems to

The surface agitation does increase evaporation.