DO NOT.. I repeat DO NOT use black silicone on the bottom panel
the bottom of these tanks is made of slate.. and silicone WILL NOT stick to slate
if you need to reseal the bottom.. you have to put a piece of glass on top of the slate and then silicone that into place
I learned this the hard way... it will appear to seal.. untill 2 days later and it falls apart causing disaster
Note To Self:
Read entire post before putting in my two cents... lol
you already said everything that I warned you about.. I just failed to read

Do you have a tank with glass over the slate then? If so, do you have any pics? I am wondering how it is going to look.