Plumbing issue, please help

[Rawsreef]

This weekend I finally took the time to add the a return pipe on one of the overflow chambers that was never finished.

Until now I've been running with only 1 return pipe. No issues as far as the water circulation.

Now that I added the second return pipe I am having an issue where the water is not draining fast enough into the sump. The water level goes above the slotted weir almost to the point of overflowing the tank.

I've tried lowering the flow which seemed to help a bit. I am wondering what's going on? I doubt it is a clog since it was working fine with the 1 pipe at a higher flow setting. But I wouldn't say it's impossible.

What are your thoughts?

Tank is set up with 2 overflows, 1 drain pipe and 1 return pipe in each overflow.

 

[Troylee]

Plug the air holes on the durso pipe and run them full siphon.

 

[Rawsreef]

Plug the air holes on the durso pipe and run them full siphon.

I don't remember if there are holes or not. I think there might be on the first 90. I will look into that as soon as I get home

 

[Troylee]

Appears to be one here.. you’ll need a gate or ball valve on the drains to tune the flow if you don’t have them now,

 

[Rawsreef]

Appears to be one here.. you’ll need a gate or ball valve on the drains to tune the flow if you don’t have them now,

Good catch lol I didn't even notice those. I vaguely remember a larger hole probably 1/2" size on the side of that 90⁰ elbow. Not sure if that has the same function. But I will look further into it and post findings. Thank you!

 

[Troylee]

Good catch lol I didn't even notice those. I vaguely remember a larger hole probably 1/2" size on the side of that 90⁰ elbow. Not sure if that has the same function. But I will look further into it and post findings. Thank you!

Any holes you wanna seal up to run full siphon.. wrap them in tape or super glue them shut etc… or if that top 90° is removable just replace it with one that’s not drilled.. a 1” drain on full siphon can take anything you’re gonna throw at it..