Hydor Slim Skim Nano micro bubble problem

[pat18]

Does anyone know why or how you could fix the problem that the skimmer releases a TON of micro bubbles whenever i feed, and doesn't stop until the next day where it is still releasing small amounts of micro bubbles. It has been running for almost a month, and no food gets into the motor so it is not getting clogged. Also it doesn't always skim, sometimes it just doesn't produce any foam, and just bubbles. Also the water depth is about in the middle of the grates so that it surface skims. Is there a way of stopping the micro bubbles from exiting?