Saltyfish
Banned
Can you clarify that a little?
do you have a sump?
do you pull the water from the sump?
do you push it back into the same chamber of the sump you are pulling from?
after all if the overflow goes too fast you are just mixing the good with the bad.
If the overflow goes just right your overflow acts as a pre skimmer (so to say) and all the oils and proteins on the top of the water go into your sump.
Think of it as a blender. The fast you go the more is mixes. The more it mixes the harder it is to tell the juice from the water (when making juice).
Same sort of thing with oils from fish , corals, proteins etc that sits on the top of the water.