I've done a bunch, some are easier to strip than others, not sure why, maybe age/type of silicone.
My advice:
Buy one of those plastic holders and a box of razor blades.
Clean the tank well with vinegar prior to starting, especially around the seams. Any mineral residue or grit will dull your blade and abrade the glass.
Toss the old blade after every seam and use a new one. You will spend a couple extra bucks, but it's worth it.
Be sure not to leave any film of old silicone because the new stuff won't stick to old silicone. Make sure you have good lighting so you can see any residue.
Don't use hardware store caulking. Not only is a good RTV silicone stronger, it also spreads nicer and cures clearer. I can't remember the exact kind I used (I ordered it from Grainger for about $8/tube), but there are several threads on the "best" brand of silicone.
Do the best you can sealing around the top trim, especially in the corners - it is really annoying to get a slow drip from condensation/splashing making its way through the trim.