Hello, I have a recirculating hydro system built with PVC and have 48 holes to fill with strawberries. Question is, since coco coir and LECO rocks (clay balls) work well for aeration, I'm wondering if anyone has come up with a material that works well to hold in the coco coir in the pots without it falling out (using 3" pots for now) and therefore doesn't clog things up but will, most importantly, let the strawberry roots out into the stream of water below? Ideas? Thanks