Searched everywhere for bentonite. Found a source 100 miles off in Birmingham, AL $12 for 50lb bags. Not good yet I needed a modest amount to supplement a DB-200 polymer treatment I'm trying. Then, the next day I find an ag store less than 5 miles away sells it for $10. Then I break out 2 25lb kitty litter bags I bought last summer and compared 'em with the bentonite.
Bentonite (benseal) small granular, spreads easily $10-$12per50lb
regular(red bag)
Special Kitty litter medium chips(2.5X's size of benzil)$6per50lb
premium (yellow bag)
Special Kitty litter med chips (2.5X's size of benzil) $8per50lb
The litter comes in 25lb bags piled up on pallets in Walmarts around Northern Alabama and also my primary residence back in Bakersfield California. I don't know it's purity but when I mix water with it in my hand, it swells and feels the same. The only difference I could see with the premium kitty litter was it had perfumy speckles. I think the $2.78 regular litter would work as well and it's a dollar per bag less.
Seems a while back someone else around Alabam was looking for bentonite. If Walmart can get clay based Special Kitty litter and with all their marketing might, sell it for less, then folks may have an alternative to expensive shipping for bentonite. Wonder if you could go in to Walmart, talk to a supervisor, drive around back and have a forklift load a pallet into your truck? Just thinking out loud.
This line of thinking isn't researched or verified, so do your own homework before investing.
