How long should the photoperiod be?
Under normal circumstances, a photoperiod of 8 to 10 hours should be sufficient. More, and you run the risk of an algae bloom and/or stressing your corals due to an extended photoperiod. With less, your corals and freshwater plants may not do as well due to a lack of sufficient photoperiod. The easiest way to regulate photoperiod is to place your lights on a timer. This allows for an automatic day/night cycle without you needing to be there. Some reef hobbyists have arranged their lighting so that the actinic 03 bulbs come on first, then the metal halide(s), this being done so as not to photoshock the corals. It should be remembered that although blue light may not appear bright to us, it IS bright to the corals so there may be no benefit to doing this. One problem that faces hobbyists is that they are not home a good portion of the day. To compensate for this, they leave the lights on well past the 10 to 12 hours actually needed. Here again, the timers come into play. It may be to you
