Tubing, Barbs & Restricting Flow
I'm setting up a new tank using an Eheim 2217 with it's 5/8" tubing on the intake and 1/2" to the spray bar. I'm building an external CO2 reactor with bio balls that feeds from the intake (on the 5/8" tubing) into the cannister. I realize this may be heretical to some but it's the set-up recommended by the designer and worked well on an earlier set-up with an Eheim 2213 with it's 1/2" tubing and 1/2" I.D. barbs screwed into the external reactor.
It's hard to find 5/8" barbs ("male adaptor" in the catalog) so I ordered two on line but discovered when I got them that the 5/8" was for the external diameter of the tubing and the internal diameter was 1/2". Will the 1/2" I.D. of the barbs really make a difference in the cannister's flow rate and, if so, is there a solution that I should follow? The new tank will be a 75 gallon and the filter is rated for a larger tank, but I'm concerned that between the restricting barbs and the bio balls (5) that the flow will be greatly reduced. I guess I'm wondering whether it will make a difference to be concerned about.