Hey reefrunner, can you set the whitebalance on a dig. coolpix 3100?
According to dpreview.com you can, but I've never used your model so I'm not certain how to do it. On the 995, you would go into the menu, go to white balance, go to manual or preset, then when you open that the lens will zoom in and a window will be on the screen asking if you want to sample or if you want to exit. make sure something white (In the aquarium) fills the window and press sample. I have been successful using the sandbed and using white coffee filters, just put one over the lens (2 or 3 works slightly better IMO
) and press sample. With the 995, I could not take a white balance preset with the flash firing, I don't know if the 3100 will, if it will and your going to use the flash, make sure it's up when you sample the white balance, if it won't, I had good luck shooting with the flash on floresceant WB setting and then doing levels adjustment in PS.