as for the member with the question about silicone... I use to work at a LFS and i had to scrape out the old silicone and replace it in 6 55 gallon tanks... it took a entire day... and i got high off the fumes... while working, that was amusing in itself... but the silicone works great.. on a smaller scale i resealed my friends 55 gallon tank and it worked great, no leaks.. its been up for two years so far no problem