My pond is a 20000 gallon rectangle with six 4" aerated BDs, ZERO TPRs, and almost no slope to the BDs. We do NOT get any build-up on our pond floor....
It is amazing that they can grow back their legs or feet. Where do you keep your axolotls? I remember you were keeping them in your greenhouse before...
Thanks everyone for the great feedback so far - it seems like more BDs is the generally accepted path so far. I did not consider pockets for floating...