I also had this problem when i cleaned my brush after each use with gel cleaner, then i was told i didn't have to do this, just remove the excess gel with a lint free wipe and cover it with a clean wipe (or 2) to avoid dust getting on it. This way the brush doesn't cointain any air when i dip it on the gel, witch was what used to be the sourse of those tiny bubbles. The only thing about this method is that i have to have 2 brushes, one for clear gel, and one for white gel.