I kinda have been cheating a little bit. If you take a picture using the RAW format and edit it, you can manually adjust your kelvin temperature in the editor until the picture colors look good. I think I usually find that a Kelvin temp around 6500-7000 works out in my tank. Think of it this way, if your are using MH bulbs, they should have a kelvin rating right on them, you could just start out with that number and see how it comes out, however, I think actinics will tend to bring the temperature number down quite a bit. My lights are T5 with 10k white bulbs and actinics. Then if your camera has a kelvin white balance option, select that option and set your cameras kelvin temperature to the number you have found to work out good when editing the RAW image, if that makes sense. It should get you pretty close, and then of course you can still edit it to make it perfect. I think depending on what you are shooting in the tank, up high, under shade, or under full lights, can throw colors off even as you just move around your tank taking pictures. The problem with setting your white balance to a white plate under actinics is you are looking at a white plate that is blue from the lights, which is what you want, a blue plate, thats what the lights are supposed to do. So if you tell your camera that the "blue plate" is actually white, then it adjusts the camera settings so that if you take a picture of the plate again, it will appear white, so you can only imagine what that would do to the colors of the corals, in effect you are negating the effects of the actinics.
. i like how much open room there is what are the dimensions?
