Another thing I just discovered, it was always a pain to get additive from the jug into the bottles without a mess, and I was loading up my recyclables bin when I noticed one of those new generation liquid laundry detergent gallon jugs, the ones designed to sit right on the washer and have the push-button spigot. I know that the jugs are polyethelene, i wasn't so sure about the valve parts, but I thought if it could withstand the additive chemicals, it would work wonderully in filling up my 4oz. bottles. So I VERY thoroughly rinsed out the jug multiple times to remove any soap residue and let it drain/dry. Then I did it again. Then I put a bit of PS in the jug and tilted it so the additive was in direct contact with the valve guts, and set it over a plastic bucket overnight to see if it would leak. After 24 hours it seems to be fine, so I poured the remaining PS into it and trial filled my remaining 4oz bottles. IT WORKS GREAT! Another plus is that I can store the jug upright with the valve not in contact with the additive so no leaks are possible. I just drop it down into position as needed, fill up my bottles, and set it back upright. So far it seems to be a great system.