My silver century only makes pea sized bubbles...why?

[Arne]

I tried anything from different wattage bulbs to removing the reflector and using a dimmer but no matter what I do the silver century always makes many pea sized bubbles all the time...there has to be a way for it to act normally because when I just got it, it ran just like a normal lava lamp one evening...but never again.

Any ideas what I can do here? I dont care for this pea flow at all and also I dont wanne sell it like this...which is a bit sad as I even have the original box and paperwork but with this beaviour its worthless for me.