DIY Overflow trickling?

[d3co]

Hi guys first time poster here.

Long story short, I've built an Overflow apparatus using PVC, with the weir for in-tank level method. Problem is, its literally trickling. Ive only cemented the U joints for now, as I adjust for decent flow before I lock it in.

Whats missing from the photo is a PVC pipe point upwards tallers then the rest. Which I fill up with water to prime using the method seen in King of DIYS vid, block the outflow, fill up the pipe, then release the outflow.

Ive fiddled around with it, and I can sort of stop and restart the flow. So im guessing somethings right.
My theory is maybe the levels of my bends are wrong?



Find attached the Design and a photo of it.

 

[TheWolfman]

That looks correct. It’s could be possible that you might not be getting all the air out of the overflow when you are priming it. When I prime it, I put the pipe under water and assemble it and then put it on the tank. How much flow are you putting through the overflow? What size pipe? Here’s a picture of the one I made for a drip overflow for reference.