Is it new? If so, then this is probably just a break in problem. Otherwise, you should be able to adjust the water flow and air intake with the air valve difusser. The more you let in, the more bubbles.
i have a seaclone. everytime i put my hand in the water the bubbles go crazy. It should stop soon my has been up around the same time. I find if I turn it up so it makes loud noise then it stops crazy bubble making.
yeh i've had one set up in a 90 gal for about 9 months now it will eventually stop but after that you will constantly be toying with the air intake flow. hang in there <img src="graemlins//angel.gif" border="0" alt="[angel]" />
the best thing to do is just keep adjusting it until you figure out the right settings. if it dumps bubble's no matter what you could always put a peice of filter foam over the out flow,thats what i did at first. the promblem eventually cleard up itself. hope this helps.