Wait for it... "It Depends"
Bottoms diffusers are designed to turn the water over and expose the bottom layer of water to the atmosphere where it will take on O2. Makes most all the water in a pond livable. As I understand it, it will improve the water quality, but I have experienced a diffuser kicking up some detritus along with some dirt from the bottom of the pond. But, I have also seen it clear up a dense bloom faster than without having aeration. Mr. Lusk has said in his facebook sessions that in a small pond it would be wise to have both bottom diffuser along surface aeration. I am no expert but have some experience with bottom diffusers. Hope this helps out a little.
PS, never read or remember reading where Wheat straw helps to clear green water, but have read where Barley might help.
