RTV is an adhesive silicone rated for 40lbs/sq inch. Anyone who has worked with RTV and with GE I/II can tell you they are not the same in consistency when cured. The GE I/II doesn't adhere in the same manner as the RTV series silicone.
It was stated on the aqaurium silicone sticky at the top of the DIY forum. I also looked it up and several other forums also say the same thing.
also the advisories are aparently the same on both bottles which further supports this theory.
AND only recently did GE add a Not safe for aqauriums label to the silicone (used to say safe for aquariums) and at the EXACT same time all-glass started "making" their own silicone, which is labeled safe for aqauriums this is probably because some percentage of the mark up is payed back to GE.
it's actualy very common with everything from silicone to flourescent light fixtures/ballasts
yes it adheres better to glass than GE I alegedly.
Personaly i say go with the best silicone if the silicone is going to be the only thing holding the tank together. But if it has trim it's perfectly safe to use GE I
and for sumps/glueing stuff together don't waste your money just use GE I.
My tank has a frame on top and bottom. Dose it matter if the frame is not connected in the corners? The frame has angle cut corners that butt together...