Of course like everything else on here everyone will have their own opinions. I have used recently(within the last 8 months) for 2 tanks, GE Silicone II in black but the version that has 0 mention of mildew resistance or bio seal. It's the windows and doors type. The tanks were a 20 Gallon that i have a small colony of Demasoni juvenille's in and the other a 50 that houses FW angels, Clown loaches, black neon tetras, and a dwarf gourami.

Both tanks have been fine ever since the resilicone job but i will make mention that i did allow a week to cure after redoing it.

This is from personal experience and not hearsay but obviously it's buyer beware all the same.

sounds like the bottle I have, I wont be using the tank for a few months anyways so I will re seal it then leave it before I even test with water.

I found GE silicon 1 at HD the other day, it's hidden on the bottom shelf at the store out here. Not sure if your store's the same layout, but they where hiding in plain sight. I swear they are part ninja or something though... i had to ask where to find it.

I'm going to have to look for this stuff!