I know this is an old post I just bought the kangertech minisub tank yesterday and decided I was going to clean it and change the rubber colors after first use and I let the glass soak in hot water tried everything. I seen where someone said use a razor blade to crack the seal, I didnt use the blade instead I tried my pinkie finger nail and it cracked the glass very fast. Finished breaking it off with a wrench. Luckily it had a replacement pryax glass with it. Now the glass comes off effortlessly. Its redicilous how tight kangertech has the glass hooked onto the tip connector. Another thing I noticed is there is a rubber piece thats supposed to be on the air flow base. It was somehow stuck inside on the very bottom pryex glass.I had no idea it was supposed to even go on the air flow base until assembling the extra glass after the first one broke. Overall the glass is very weak and im afraid to even twist on it anymore. Do not believe this tank should be worth 45$ it shouldnt be that difficult to disassemble a damn tank. If it had not came with an extra pyrex glass I would be one ...... off s.o.b. just thought I would share so in case someone is wanting to buy this tank.