waterproofing

Hi all, long time reader first time posting! I recently found a unique cylindrical glass container that I would love to turn into a small (4 gal or so) neocaridina shrimp tank or even possibly just a plant tank, but it has a piece of metal that it sits in and acts as the bottom of the container...

Hi :) I'm planing on building a plywood tank, using local (South Africa) materials. From the experience of anyone who has used both, or one of A.B.E's Super Laykold and/or Durapond to waterproof plywood What are the advantages of one over the other? What's the life expectancy? 3 years? 10...