I have done a bit more research, both 1 and 2 are aquarium safe as long as you dont get the red tube which is kitchen and bath. the red tube has the mold inhibitors in the silicone.
also the only diffrence between 1 and 2 are tensile strength on diffrent materials, ge silicone 1 has the better glass tensile strentgh. with this said since you are not building a tank from scratch and simply are resealing, GE silicone 2 will be sufficent as long as it isnt the red tube with the mold inhibitors.