That won't do a thing to fix a leaking tank. The "inside" silicone is cosmetic only!
I've done it correctly a couple times and it IS NOT EASY! You must completely disassemble the tank. All 5 panels must be cleaned of all traces of silicone, and then you have to put it all back together, and the "silicone" you get from HD/Lowes is not the correct type - yuo need silicone adhesive (momentive RTV or similar) not silicone sealant (GE type I)
If it leaks I would just go buy another tank.
^^^This^^^
See above
And ^^^This^^^