cpr aquafuge

I bought this small CPR HOB Refugium from Aquacave. https://www.aquacave.com/aqua-fuge-2-hang-on-refugium-small-by-cpr-aquatic.html I had read awesome reviews about these guys and thought I'd try it out on my JBJ 45, but now reading I'm wondering if I got too small of a size? My ultimate goal...

I have an original cpr hob refugium.. acrylic. I have had it since the early 2000's I believe it is a second generation if I recall correctly. 13 inches long 4.5 inches wide and 12 inches in depth. no pump.. intake is about 3/4 of an inch. the last couple times I used it I attached a original MJ...