skimmer wet 1 day and dry the next....what is going on?

[wetWolger]

I am using a moded bak-pak (airpump with limewood airstone) on my 46gal bow. For some reason my skimmer can not decide if it wants to skim dry or wet. One day it will be skimming really really dry.....I wont change ANYTHING, and the next day the skimmer is full of really really wet skimate. Has anyone else had this? What would cause such a reaction? It never used to do this. Thanks