Hi, anthony,

Sand as a base compacts well but it has a problem....it washes out easily. That sure sounds like your issue.

If that's it, I would try hard to redirect the water so the washout wouldn't occur. Screenings (crushed rock) are a little more resistant but any fill will wash if the water flow is fast enough.

Now, the fix.....I'm not sure. I would drain as a last resort. I'm not very familiar with AG pools but I think getting that liner back in place may be a real hassle. I would try everything else I could think of first. Some AG folks will be along soon and probably have experience with this issue. Wait to hear from them before you drain.