Depends on a few things. How viscous the substance you're filtering is, what size particles are being filtered, etc. I assume you're filtering tren. I've gotten anywhere from 20ml's to 100ml's through one filter. Your best bet is to heat the tren on the stove and it'll filter much easier.
It's not tren but it is oil (EQ)....Another Q?.... and this may sound dumb but....can you use any size needle for the filtering or does it have to be 18 gauge?