An additional comment - some here have advocated and disscused the ability of bottom aeration to help improve the community of invertebrates that inhabit the bottom muck. Invertebrates such as worms and insect larvae will literally eat the deatd organic material if oxygen is present at the bottom layer.
With oxygen on the bottom above the muck, the addition of microbes or commercial, bacterial, sludge, blends can speed up the digestion of bottom muck. I am not aware of any scientific studies that prove this, but several on this forum and others outside this forum swear by the benefit of microbe additions to help digest, reduce, and decompose bottom muck when bottom aeration is used to keep oxygen in the bottom zone in order for the decomposing microbes to do their "job".
