i use a lenz filter, it has a stainless steal element you can clean, so after you buy it, no more elements to buy, you can get them on ebay, the one i use is a dh750 100,
if you use a large oil tank (200+ gallon) and only draw 6-8 inches from bottom, alot of your oil particles will settle to the bottom of the tank, if you draw directly off the bottom your filter will plug much faster!