Waterbox 165 manifold issue

[FishN00b83]

I have a Waterbox 165 FRAG tank that has been running for 6-7 months now. The return pump I am using is an octo varios 6 currently on setting 2. I recently (over the last couple of days) installed a 40w UV and connected it to one of the manifold outputs off the return. Before the UV the pump setting was great, but now with the extra needs I have tried setting 3 to 5. This has not gotten me close to the 250gph that the UV needs. I am currently getting 75gph and i would like to be in the 150-250 range.

The UV has a 3/4 barb fittings so I used a couple of inches of 3/4 braided tubing and reduced it to 5/8 to run it to the manifold. If I do the reverse and use mostly 3/4 braided and just reduce it at the end do you think id get more gph? Is it dictated by the smallest point? 75gph doesnt make a lot of sense to me right now.

 

[blaxsun]

Your manifold is 5/8", yes? I don't think it would make a huge difference one way or the other. You should be able to get at least 750-800Gph out of the pump @100%, so I'm wondering if the issue is with the manifold?

 

[FishN00b83]

yeah its 5/8ths. What issues could the manifold have? water seems to be flowing fine and I have a course filter pad before the return section to prevent anything getting in there.