Wondering if anyone has knowledge of this.

I bought a bag of smashed oyster shell chicken grit from the farmers
coop. Chicken grit has been recommended as a good way to increase
drainage for young maples in pots. (I also use sepiolite or other
mineral cat litter to hold water, oxygen and make rougher structure.)
But they may be talking about gravel, not shell.

I'm worried about increasing pH or getting too much calcium to the roots
as some of the mix is quite dusty, although most pieces are several mills.

Am I worried for nothing? I potted up 10 good 2 liter palmatums as an
experiment, but actually I'd quite like to use the stuff and not have it
sit around for a year...

Thanks,

-E