Ray
Are you sure the I.D. isn't 1/2"?
I have the same diffuser over my BD in the pond. I got it this last Fall in Japan. Going to get a few more this year if possible. I'm saving that web address and ph# for the guys you got your replacement hose from so I can order more, that way I'll have it on hand when needed. BTW, how big are your moving bed filter tanks and how much air do you pump to each tank?
Mike