Need a possible diagnosis...

Hello,

First off I'd like to say that I am completely new to lava lamps. I've always wanted one, and as of recently I have acquired one that was previously used. Starting out, I knew nothing about lava lamps, aside from they needed some time to heat up. My research brought me here to this site which has been hugely helpful in understanding these amazing lamps.

Anyway, completely off topic there. My first run of it seemed okay, I wasn't sure what to expect exactly but it looked good. Once it cooled I had moved it to my room. Over the next few days I ran it and it seemed good and then suddenly the other day it became very sluggish, huge amounts stretching up at once but just lingering as a mass. It was like this for hours almost unchanging, and I was about to consider it dead. Then on a whim I turned off my ceiling fan, lo and behold it started working again and I got to enjoy it in a stuffy room.

Now there is movement, but there are tons of bubbles in the goo and I get a lot of the teeny balls. The bigger ones also tend to linger at the top in a cluster, not exactly melding together or anything like they had been before. I'm not sure if this is normal, or what or if it's just from its age, which I've yet to decipher from the code on the cap, it's not like any of the ones I've seen listed here. I'm adding a few pics to gather some opinions. If needed for observation I can provide some video.