Welcome to the forum. It is always good to see first posts from new members.
I am not sure if I can answer your question or not, so
I have used rock (rip rap) to reduce erosion. It is only mildly successful. I would guess there is a minor bit of aeration as the water spalshes on the rocks, the wind blows almost every day and I often have a 4" splash line. My pond is sandy clay and there was not a rock any where on my property, I brought all of them in. So I don't think there is a ratio. My rocks are cemented in place, I started out just stacking them, but the rain washed them into the pond, seems sandy clay is very slippery.
I am going to guess that whatever you put on or near the bottom would depend on you pond goals, is this going to be a kids pond? trophy trout?
Read the previous posts that look like they might pertain to your goals and you will get a better idea of where you are headed and maybe tailor your questions to more specific areas that concertn you. There are many many qualified people here, yours truly not included, who will be more than willing to help you. The more information you rpovide the more you will receive in return. Good luck.
