Bentonite clumping cat litter (Hazel Grove SK7)

I'm using this for lining a pond, as I would prefer not to use a plastic or rubber liner. This stuff is virtually identical to puddling clay used to line canals and large ponds. It's a bit of an experiment and may not work 100%, but worth a go. I've already done the deepest part of the pond and it sort of works. I would appreciate any advice too!