I've got the same unit on my SW
tank. Not sure how old your filter unit is, but whenever I have bubble issues, a really good cleaning normally fixes the problem. Areas to look at... make sure all the sealing surfaces where the little foam gaskets seat on are smooth and free of debris. Make sure the o-ring in the lid is properly seated. Run the little yellow cleaning rod up and down that clear tube on the central tube to make sure all the gunk is out of it.
The filter will under normal operation put out a burst of bubbles now and then as it purges itself of air that normally becomes trapped in it. And if that purge goes on for a little while, yeah... it can take 10 minutes or so for things to clear out. But I haven't had any real issues with mine. Just make sure that before you snap the lid back on, you've filled the cannister as far as possible to the brim with water, while holding down the cannister and top clear piece. (Those tend to float to the top, but I'm sure you've figured that out.)
Oh... another thing I just thought of - have you made sure it's level? With the lid off, you should be able to fill it up to the rim and gauge the level.