Hi there,
I get the same problem with my older lamps, and havnt found a solution yet...I think it has something to do with the "surficant", and have found myself living with it by thinking that its an old lamp!!
David
I put it on a dimmer last night and it probably is down to about 25-30 watts and that helped majorly, still has bubbles, but way smaller and much less of them. The cool thing is it has the slowest flow I have ever seen, almost like the slow glitterball! I will have to upload a picture tonight.