I agree, removing the insert probably wouldn't leave it in desirable condition as a fish tank. I can only imagine how tough it would be to do all that work only to remove it. I know for me, it would be worth more to me personally than what the going rate would be. I imagine it's probably the same for you. It's just such a small market. I might set a bottom dollar and don't budge on it, decide what it's worth to you and if nobody offers that or more, maybe hold on to it. If I recall, the main reason you want to sell it is the inconvenience of moving it right? I've moved my fish tanks a few times, plus my brothers once and a buddies (all 55 gallon) and that's always a nightmare due to the weight and the water. So I would imagine a tank your size is a pain too. But maybe think of it this way: after the added hassle of moving it, will you be glad to still have it? Does that outweigh selling it and not getting what you want for it? Would you miss it if you sold it? Just some thoughts. That would probably be what was going through my head if I was in your situation.