Stupid question: Apoxy is expensive. Water proofing agents in general are expensive, at least the ones I have been looking at. So, would it be more cost effective, though not as nice looking, to built the GB in wood framing, and line with the pond liners than to ferro it? I really like the look of the work you have done here, but when I price it....it just doesn't add up to be something affordable. I have looked at building a cinder block GB and lining it, wood ones, plywood ones, I have used gutters but only good for really shallow roots. Generaly the plastic tubs are too small, livestock troughs are either expensive or galvanized. Maybe I am just being a wuss here and not wanting to crack the budget. Ideas/Advice?