If you truly have good clay then don't waste your money on that other stuff. That stuff has its purposes but with having a good clay resource you have what you need already. I would suspect that it is bad construction causing the leak. Spend your money fixing it properly. I live in the Dayton area too and our soils are very heavy with clay so there should be plenty of clay available to properly fix the pond. The ess 13 will probably run you at least $5,000 plus shipping from Arizona, a sheepsfoot can be delivered to your site for about $300 or so for the day if you want to do it yourself.
I would highly recommend contacting your soil and water district, they are very helpful and knowledgeable
