Thanks for the advice! You guys really know your stuff!

To be clear(no pun intended) I’m not opposed to fish, or being sterile/not sterile. I only stated that to let you know I would gladly sacrifice fish for clarity. If there was a chemical that made it clear but killed fish I’d be ok with it.

Most ponds we dig are located in a runoff terrain to maximize watershed area. This pond I was thinking of building in such a way that runoff would not enter the pond at all. I have a good spring and a solar pump I can use to pump spring water directly into it.

I have a friend in the Houston area who built on a few years ago and lined it with stabilized sand (10:1) mixture of sand and Portland concrete. His worked pretty well but we don’t have any local sources for it and the truck would make in too expensive.