Hi Scott,
Thanks for your inquiry. The lighting needed will depend on the type coral that you plan to keep. If you are planning to keep corals that require low to moderate lighting, three 175W lamps (or two 250W lamps) should do the job nicely. This lighting setup would work great for leathers corals, LPS coral, polyps and maybe even a few SPS corals and anemones near the top of the tank.
If you are looking to keep corals that need more intense lighting, either three 250W lamps or two 400W lamps would be your best choice. This lighting setup would be great for SPS coral, clam, anemones. Soft coral and LPS corals should be placed on the low half of the tank with this lighting.
For an all-out SPS tank where color and growth is most important, three 400W metal halides would be the ideal setup.
With the retrofit kits, I would recommend either the PFO magnetic retrofit kits (
http://www.marinedepot.com/a_lt_mh_pfo.asp?CartId=) or the IceCap electronic retrofit kit (
http://www.marinedepot.com/a_lt_mh_icecapsystem.asp?CartId=). Light output between the two would be about the same. The IceCap, although more expensive, will be more energy efficient and allow the bulb to last longer as it features a high-frequency start instead of a high-voltage start.
Please do not hesitate to contact us if you have any further questions.
Sincerely,
Joseph
Marine Depot Customer Service
www.marinedepot.com
