Brent, I never thought to stop the reaction while the frame's still in the bath. I remove the frame, rinse off, hang to drain & dry, then add baking soda to the bath. Sometimes there's a little residue on the frame, I clean off with a soft sponge or rag and gloved hands.

Classtime, your Raleigh looks great. After first starting "kiddie pool" I built up a similar frame box except without the top & bottom. I added hinges at the corner so I can easily re-assemble adjust the angles a little bit. I have a pebble filled path on my side yard. I just lay the box frame on the rocks, added a heavy-duty shower curtain, and then fil it up and cover up with some plywood to keep the dog from jumping in.

I do suggest you try to fill the gaps in the frame next time. Less OA to deal with at the end. That large plastic tub (filled with plain water and some large rocks) might fit in the main triangle.