Metal Halide bulbs

How many metal halide bulbs does a tank need?
Recommended : one metal halide lamp for every 2 feet of tank length.

What wattage matal halide bulb to use? 
Tank height 18" to 36" = MH 175w 
Tank height 24" to 36" = MH 250w
Tank height 24" to 60' = MH 400w

Upgrade your metal halide to a higher Kelvin rating (whiter and bluer bulbs) and or higher wattage (brighter) email for price quoteon different upgrades.