I believe there are superior products out now compared to the aqua clay (AquaBlok). I believe you are referring to the aggregate (gravel) that has been coated in bentonite? However, I am definitely not an expert on that question!

You should probably perform a forum search for SoilFloc. Many members have had good success with that product. (If he drops into this thread, then you should probably contact teehjaeh57. He is an expert on that product and pond sealing in general.)

If you have acceptable clay AND rebuild the core trench correctly, then your pond should not leak. If it does still leak after your "redo", then I believe you can still add SoilFloc after the fact and improve your pond sealing.

Good luck on your pond project!