I have a 75 gallon saltwater with some live rock and 1 lunare wrasse in it. I am running a coralife skimmer off the back and most of the time it works great. I can set it to filter what they call dry but every now and then out of the blue it starts pushing foam into the collection cup and filling it up in a matter of minutes. I havre cleaned it , tore it apart to see if I can find anything,adjusted levels in the filter and the aquarium water. Nothing makes a difference! Is there a reason that this is happening? thanks for any advice in advance!