HELP - Slow tank Leak

[cbinboston]

Long time lurker, but I need help big time.
I saw some condensed material around the bottom of my freshwater tank today, and found that it was slightly moist. That leads me to believe that I have a slow leak in the bottom of my tank. I'm going out to get a big rubbermaid container to drain the tank later today... but what is the best way to find a slow leak and repair it?
Any help appreciated.

 

[dvincent]

Is the tank glass or acrylic?

 

[cbinboston]

Glass.

 

[hurt]

Aquarium silicone

 

[cbinboston]

Yeah, I figured that out. However, should I remove all of the old silicone, or just lay a new bead down over the old stuff?

 

[mike_cmu04]

i had a 55 that leaked along the bottom seam and the only way i could stop the leak was to remove the old silicone. however after a couple of months with no leaks it began leaking again and i put tons of silicone on the seam.