Can anyone tell me what moderate lighting means. A lot of online fish sites say the corals require moderate lighting. I have a 216 Watt T5 fixture and think it is equivlant to around 300 Watts of a basic fixture. Is this moderate for a 75 gallon?
Low-Moderate-High ratings, in order to mean anything, would have to be related to PAR levels at the depth of water that you were keeping specimens at. What that means is that it is very possible to have all of those light levels in a given tank. What the lighting level would then dictate is the water depth you keep them at.
i have the current pro T-5 6x54wHO fixture with individule reflectors. This is high-moderate lighting. You have a 75g which is a bit shorter then my 90g. If you get a fixture like mine either the Current or Tek you will have more then enough light. I have LPS, SPS, and clams
If you have access to an Apogee PAR/Quantum meter, then you can measure the levels in terms of the PAR, moderate lighting will be somewhere between 50 to 80 micromole/m2/sec. Coral examples and PAR values after James Fatheree's unpublished work in the area for growing and established colonies without presence of specimen losses nor bleaching: