100 gallons of sap put through RO gave me 40 gallons of concentrate to evaporate down to four gallons to finish off filtering along the way several times at transfers and then again into the bottler ,four cone prefilters dampened andinto wool finish cone ,again, dampened ,3/4 went fine ,one prefilter to the next till just the wool filter remained .and would not give up the last two quarts .what a pain . is it just me !!!!! we ended up with a gallon and a half or so ..no sap yesterday