I was looking into what it would take to make my hydro lettuce into a certified organic product. Apparently, all of the hydro system has to be constructed with only "food safe" materials. They make food safe pond liners, and I have seen organic hydro lettuce grown in a raft system. But I think the aeration is done with an air pump. I can't seem to find food safe water pumps in the size I need. They make small ones for beer brewing and solar collectors, but they are too small. I would like a food safe mag-drive 300-600gph pump, or even something larger like a sump pump would be fine in a bigger system. But I don't think such a product exists???