Need some ideas....

[Delphinus]

I'm not sure I'd take a hammer to something that large. I've smashed small tanks like 20g's that were sumps to get them out of a tight tank stand, and found myself cleaning shards for months ever after.

The two things I'd consider is 1) build a temporary frame to compensate for the missing panel, or 2) try something like a guitar string to disassemble the panels. (Never tried that so don't know how well it works, but I've heard it suggested in the past.)

Oh and yeah anyhow, tempered vs. starphire. Not the same. You can have tempered starphire glass, non-tempered starphire, etc. Whether it's tempered or not depends probably on the dimensions of the tank. At 320g it's not inconceivable that it is (tempered) (my 280g's front glass is tempered 1/2 starphire). But if the tank is short or shallow its possible that it isn't. Supposedly you can tell if glass is tempered or not by looking at it with polarized sunglasses (the polarization will pick up on the wavy lines that you can't ordinarily see otherwise, should look like a criss crossing pattern ... I think. I guess I should check with my own tank whether this is an urban myth or not. )

Anyhow, whatever you decide, good luck. Hope the remaining panels are salvageable. Given the price of starphire these days it would be a shame to see it go to waste.