So here is a newbie question

Barley (3/16" x 3/32")

Buckwheat #4 (3/32" x 3/64")

Buckwheat #5 (3/64" x 100M)

Who uses these coals and for what?

Losch stokers could burn barely...you will find some of them still operating in commercial settings and a few scattered homes.

I was told the smaller sizes are usually sold to industrial users...water filtration, etc.

And only to add to what *Rob R.* already wrote, some of those same sizes may still be burned for fuel as another new product discussed here in this thread... New Coal Product

OMG, cabin fever has seriously set in on my good friend cn

there is a place in halzeton that does water filtration from coal. when i talked to the guy he said that there selling 50 lbs for 150 to 300 depending on size. he said that most of it was going over seas.

on another note ive been using this coal for my fish tanks for years. i get it for helping him out from time to time. i think its buckwheat # 5 there are no fines in this and its all the same size. works great for the fish tanks and the water is clear and tests good enough to drink and that's with the fish in it. side bet after one month no filter cleaning.

tank is 150 gallons fresh water with a wet dry bio filter.