What would be the best height for a constant water level in the skimmer section of a sump? I realize skimmers can be tweaked, but if you were building an overflow section that always stayed constant, what height would be optimal? I thinking around 6", but would like to hear from others. I'm probably going with a 6" diameter EuroReef, but want a sump section that would be the best possible height for most in sump skimmers.