Here is what I use. It is made by Matala. I will not say if it is better or worse than other styles or brands of diffusers because I do not know. It is all that I have ever used. But they seem to work ok for me.
At least this will give you an idea of one type of base that is available and the modifications I made to make it work like I wanted.
You would have to look up the specs to be sure, but as I recall a single 9" or a dual 9" (like the ones pictured) would both fall within the CFM your pump delivers. The single being at the high end of its capability and the dual at the low end. If it were me, I would use a dual 9".
Diffuser cleaning thread Edit: I think the most popular and preferred brand on this forum is Vertex. They also make a 9" diffuser head similar to the Matala pictured.
