Lisa do you remember if you used Matrix blocks or large stone?Sure! We installed one of these in our up flow bog:
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In the up flow bog, the water is pushed up through the "centipede". The vault is to allow for clean out - we would drop a pump in the vault and draw water down through the gravel, reversing the water flow. It works in theory - haven't had to try it yet!
I think this is what they call the "mini" version of the centipede and snorkel. We have the larger version at the opposite end of the pond in the "down flow bog" where the pump lives in the vault. (I can't ever use the term "bog" without missing @Meyer Jordan and his reminder that these are more accurately called something else... do you think I can remember what he called them??)
Basically what I am asking is how was the rest of the bog constructed 6" plus rock for a foot, then 1- 2" for a foot with three eighths pea stone for 6" on top? I love the theory of the settlement chamber but I can't find the recommended sizes and thicknesses of stone