[quote author=tuberider link=topic=6585.msg84851#msg84851 date=1235696092]
I get mine through my local "water store", you may have one near you. Also I see them at OSH every now and again.
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Those at OSH suck. I've tried em and wasted my money
I'm not sure where you are pianotips but berkeley's secret garden on university has ro membranes.. Call some local hydroponics shops in your area.. I bet at least one of them carries something..