I have a SWG and add acid 1 or 2 times a week, about a quart at a time. I pour directly from the jug into the pool by a return with the pump running. No measuring, just go by feel for about 1/4 jug. Slowly pour it in a couple of inches above the water so it comes out in a steady stream and does not "glug" out. For me, getting the seal off a new jug is the time I'm most likely to get a tiny splatter where it does not belong.