Collecting up parts for my aeration system. I have my Gast pump, airline to the pond, weighted line for in the pond, and now looking for diffusers.

I have been searching and reading and searching more until I am frustrated so I am looking for some help.

I read that Vertex has the better diffuser due to smaller slits in the membrane so I searched and apparently my GOOGLE foo is weak today as I don't find anyplace selling just a diffuser that I can throw in my cart and buy. I do find EDI FlexAir at several online stores and am about ready to simply purchase those. If I hadn't read that the Vertex is twice as efficient, I would have bought them already. Perhaps the Vertex is much more costly wouldn't be worth it but I have not been able to find them that weren't in a "kit" with all the other components.

Maybe I am incorrect in my assumptions?

Can anyone steer me to a place I can see pricing/purchase the Vertex? Or tell me I would be fine with the EDI?

Thanks in advance,
Dan