DE Filter material: coarse vs. fine

[brewmar]

New to filtering using a Velo horizontal leaf filter.

Can anyone guide me on what "size" is considered coarse and the same for fine DE media. (Darcy or micron permeability ratings?)

Thanks in advance.

John

[pbutlert]

I pre-coat with Celite Hyflo, 4-6 microns. Body feed with STD., 2-3 microns. My yeast is a high floccing strain. I use 512 for body feed with med. floccing strains, it is 3-4 microns. If you are sterile filtering with P&F filter in-line after DE filter, using 577(.7 microns) will help the sheets last longer. Your supplier should be able to cross-reference the various brands and give you ratings.

[brewmar]

thank you!

[Woolsocks]

My perlite supplier classifies 3 micron perlite as fine and 7 micron perlite as coarse. With depth filtration, though, the filtration speed and amount used as as much to do with the sharpness of the filtration as does the size of the perlite. I've used the "coarse" and "fine" grades and results have been similar except that I have to run slower when using the coarser stuff to get acceptable clarity.