another sump/plumbing related issue

[FluffySackson]

It seems my overflow is slurping air unless I completely shut off the gate valve from allowing water to flow down into my sump. I check my return pump and it was jammed and I removed anything blocking the impeller....yet it still seems something is clogged in my plumbing (return) the flow is alot weaker from the locline returns and I'm wondering what's up. Redoing the plumbing will be a chore since it's a 2 foot tall tank on a 30 inch tall stand with a tower overflow box

 

[duanes]

A few tiny snails bunched together, or rotting plant leaves, with some other detritus can easily block a return line. If possible take an old wire coat hanger, and jam it as far as you can into the pipe, and feel for a blockage especially near some pipe turns or bends, or near partially closed valves. This is part of my weekly maintenance.
I also found I needed to exercise partially closed valves at least once per week to dislodge stuff. By exercise, I mean turning them off, and on, a few times with the pump running, by doing this, a burp of brown junk would always spew out.
It always amazes me to the extent that a strand of plant fiber the width of a human hair, and wrapped around an impeller can easily close down a pump.

 

[FluffySackson]

I cleared the debris (it was a few flecks of silicone I razorbladed off the sump walls) but it seems no matter how finely I tune the intake, it will still slurp air.

 

[DN328]

It would be helpful to provide more information; how many drains to you have and which one is slurping water? Also, how long have you had this set-up?

When I was setting up my tank, I had to cut/lower the primary and secondary (Herbie) drains as it was air. Lowering the primary allowed it to create a full siphon given the return flow I had into the overflow.

But to good to check that nothing is blocking your return as you've done too.

 

[FluffySackson]

I just redid the plumbing altogether (it was a simple piece of pvc and a ball valve) and turned it into an herbie style system. And the flow issue was resolved, it was a hermit crab who must have crawled into it during a water change (when it was off) and met his demise. I use duck lip tips on the locline to prevent it from happening again.