I used to use it but now we live on 1.5 acres and everything is in ground. Here is where I purchased stuff:

LOS ANGELES / SAN BERNARDINO CALIFORNIA

*** TURFACE MVP - 50# 12.50 bag , OR diatomaceous
earth from an Auto Supply Store
Tomark Sports
1180-A California Avenue
Corona, CA
92881
800-959-1844

Try looking up Sporting good stores, or ask local highschools, colleges
where they get their infield supplies.

*** Crushed Granite
Look up roofing companies. A lot of the ones near me carry grit.

A-1 Grit manufactures the grit, and sells it to a number of companies through
out the west coast. Call them and see if they supply anyone near you.
1-800-266-GRIT If you get A-1 Grit you want Size #5.

Allco Roofing Materials 80# bag $5.75
8650 Garvey Avenue
Rosemead, CA 91770-3269
(626) 288-2922

*** Fir Bark
This was the hardest thing for me to find.
Al really likes "Shasta Forest Products" and I called the company to
ask for stores that carry their product.

Kellogg Garden Products
8605 Schaefer Avenue
Ontario, California

Phone: 909-673-8065

I decided to use OF Wolfinbarger. It was more affordable. Its not Shasta
brand. But it is Fir Bark.
OF Wolfinbarger 2cu ft $4.50 bag. 1/2cu Yard $26.50
5675 Francis Ave;
Chino, CA
91710
909-627-7481
http://www.ofwolfinbargerinc.com/
-They also have BARK FINES for anyone making 5:1:1 mix.

I buy Dry Stall at feed stores. Unlike the Turface, it's bright white, but otherwise similar. Be careful that you don't get Stall Dry which is a different product. I just went out to my garage to make sure that I gave you the right name

Fine orchid bark can be hard to find in large bags. I used to buy it at Flowerdale Nursery in Orange. I've used fine redwood bark too

i use gravel from either the roofing or the concrete section (don't remember which) at Home Depot

Orange County Farm supply (Orange) was selling bark of different sizes--you could bag it yourself and get the amount you want. I haven't been there for a few months, don't know if they still have it. I use pumice, which can be bought as OSH, instead of Turface.