I have an ASM G1X Skimmer on a 90gal system. Not much bio load currently, but Nitrates are reading 25ppm with 0 nitrites and 0 ammonia. I adjusted for a dry skim with bubbles coming to the top of the neck, but not overflowing. Problem is that I never get a foam head build up that spills into the collection cup. Only way to get something into the collection cup is to adjust for a wet skim. Is this normal?