OK, I'm back for a few ....
Three 400 watt bulbs is 1200 watts / 120 volts is 10 amps. A 14-2 (wire size)/15 AMP circuit should hold this without a problem. But with other equipment on your reef, you are right, you should have two circuits giving you 30 amps available. I would doubt you even have another 10 in the other stuff depending on the size of pumps and heaters and so on, for a total of 20.
Anyway, like Jason said, you can run 10-2 over there for a 30 amp circuit and then split off several outlets. Legally you will need to have outlets that are rated for 30 amps, hmmmm I forget you may need commercial receptacles.
However, it would be easier to run another 14-2 (copper is hellishly expensive now) for another circuit and give your lights their own. Buy a double breaker or two for your panel to give more space.
What is the size of the main breaker in your home? If you want, you can run down the major electrical devices in your home and I will give you an idea is you are good on load. I highly doubt there is a problem, but don't know what kind of equipment you have for your business.
For example, I am running my home on a temporary 60 breaker and 60 amp wire fed into a 200 AMP service. I am still in construction phase. This has no problem with a 1900 Sq Ft. home with 3 tom AC. electric dryer, tons of aquarium and tons of computers. In the winter I even have several heating cables and water tank heaters and have never had a problem with this is four years. (Yes I know I am slow to get things done, I am a busy guy. ;0))
Now for a VERY important question ..... what do your mean by "burned up the outlet"? Do you mean like black and melted meaning extremely hot or fire???? Again you halides will draw about 10 amps, so if you burned up an outlet there is another reason, like other things plugged into the exact same outlet. This is my main concern with what you have said. I'm with Jason, we don't want your house burning down.
Feel free to email me -
jtesdall@mapcon.com