I really don't want to have old baths in the run for the ducks, they look so tacky and messy. on watching the video it got me thinking that I could make a wooden duck pond with shiplap joints and then paint the inside with an (animal safe) bitumen type sealer/tanking.
I think if all the shiplap joints are sealed as it is being built it would make a nice smart water tank, possibly about the size of the one in the video or maybe a bit bigger, it would probably need some kind of bracing to stop the weight of water distorting it to much.
What do you reckon?