How do i remove this? Glass lip on glass tank.

[Mumma.of.two]

I have a tank that has a little glass lip just over an inch wide on all four sides. Because of this a HOB filter doesn't fit correctly causing it to sit at an angle and rattle. The outflow of water also trickles over the lip and I'm afraid it will overflow out the tank. Anyways, I've tried to remove it with a razor blade without success. I'd prefer not to have to move the tank because it's in a corner on the bottom shelf of a stand with two tanks. I would have to empty both tanks, move the top one, pull the stand out and slide the tank out of the side of the stand. It will not come out the front of the stand, it's too long and the legs get in the way.
Anyone have any ideas how to remove this?

 

[Sake]

Do you know what it's stuck on with? Is it regular silicone? I don't know of any solvents that would work. One thing you could try is heat and a putty knife. Just heat it up and keep pressing the putty knife along the seam it should give. Without knowing what it's stuck with though I can't say what fumes it will be giving off, but I know for epoxy/silicone I've used heat to soften it up and cut it out of grout joints. Only thing I'd worry about is the fumes and your fish getting hot >.<

 

[Sake]

Rimless tank...are you sure it's not on there for bracing and that it's safe to remove?

 

[Mumma.of.two]

Thanks I'm 99% sure it's silicone so I'll give heat a go. It's not structural at all. There are four of them on each side of the tank used to hold the lids in place.

 

[Sake]

Ah that makes sense! Well good luck let me know how it turns out.