Yeah, I had a 55 gallon Coral Reef aquarium in the early 90s. With stony corals you had to have CO2. I experimented with yeast CO2 reactors as the real setup was expensive.
Coral Reefs are major work and very expensive. I had two used Metal Halide street lamps, a used Protein Skimmer and tried to go cheap.
My advice - if you want to go this way is to go for the best and be prepared for a lot of work. Folks will go ahhhh, and ohhhh when they see it, but you will be fighting fireworms and parasites and chemical problems weekly.
Have heard about the new LED lights which are probably worth it. The Metal Halides evaporated the water like crazy and had problems in the summer with temperatures.
Good luck to anyone who tries it.
Thanks for the coral reef aquarium info.
I want one of these JellyAquariums
http://www.jelliquarium.com/
anyone have experience with one of them ?
I went similar route as you took. I did not use the metal halides lamps however. I just stuck to a bunch of florescents available at the time for reef oriented tanks. I had a 55gal as well. I built my own filter systems using the spinning arms, and rolls of filter in large rubber buckets with loosely fitting lids. System got destroyed after maintaining it for about four years. Left the house for a weekend of work with a small computer firm, returned into my drive way wondering why the Colorado river was pouring down my drive way. Toilet went bad just after I left on a Friday... half the house got destroyed by water damage including the reef system on the first floor living room. Lost a few thousand on that deal.
But it was an enjoyable hobby while it lasted.