so for a 8" jar with .5" media 265.45 / 7.5 sq... so this = .. 265.45 / 2.73861... then is = 96.928 rpm /65% = 63 rpm
for a 6" jar optium speed 73rpm
edit just done the calc for 3/4" media and get the same result 63 rpm ,i personally think anything around the 60's will get you great bp, i use 3/4" lead media cast like this simples!
Edited by dr thrust, 18 August 2012 - 07:40 PM.