Marshall
Turtle Keeper + CPL(H)
Not saying I am going to do this or that it will work but I am always dreaming up things to do and just thought about this one...
To make a smaller yet very strong pond you could buy one of the hard plastic shell type that are already shaped. Then you would dig a hole that was four inches deeper and about 5 or so inches larger around the sides. Next coat the bottom (outer side) of the shell with a release agent. Using appropriate concrete mix fill the bottom of the hole with the 4 inch layer and then sit the shell on top and center it before pouring the sides full with concrete. Next wait for it to set and pull your shell out and smooth out any blemishes and/or shallow spots. Voila! you have a concrete lined pond and a custom made hard lid that fits it perfectly
PS: You could also take the same shell and use it to mold as many fiberglass copy shells as you wanted...
To make a smaller yet very strong pond you could buy one of the hard plastic shell type that are already shaped. Then you would dig a hole that was four inches deeper and about 5 or so inches larger around the sides. Next coat the bottom (outer side) of the shell with a release agent. Using appropriate concrete mix fill the bottom of the hole with the 4 inch layer and then sit the shell on top and center it before pouring the sides full with concrete. Next wait for it to set and pull your shell out and smooth out any blemishes and/or shallow spots. Voila! you have a concrete lined pond and a custom made hard lid that fits it perfectly
PS: You could also take the same shell and use it to mold as many fiberglass copy shells as you wanted...