Im looking to build an sunken pond in the summer using a pond liner. The two top products that are interesting me are Laguna and Tetra. Which one of these brands has the better products IYO? I am still planning it out, and wanted to house my channel cat and whatever else I could, so I was looking for it to be around 800+ gallons. I am also having a hell of a time trying to figure out how much liner equals how many gallons, if anyone has a formula for that it would be appreciated.