New (used) tank, redid overflow and return, new dc return pump and now return is loud?

[averagesteve]

Hey all,

I bought a used 75 gallon Marineland corner overflow tank on the marketplace, I cut out all of the plumbing and redid it as a Herbie style and replumbed the return over the top since the tank only had two holes drilled. I also added a new DC return pump. I just almost finished the overflow plumbing last night (the emergency one I messed up and need more parts) but I was able to run it for a little bit and now the plumbing for the return pump is loud when I run the pump at like 75% or higher, when I run it lower, it's silent. It kinda sounds like a toilet flushing or gurgling like air in the line, the pump itself is quiet. The water level gets pretty low in the return chamber since the tank hasn't been running or topping off and the entire corner overflow drained into the sump, so it could be sucking air, but it didn't look like it was...

Just wondering if there would be any specific reason as to why the plumbing is loud on the return when the pump is running full speed. The pump itself is completely quiet. I can get a video with sound later if needed, although I'm not really good at figuring out how to post that stuff so it could be a few days lol.

Thanks in advance!

 

[KStatefan]

Pictures of setup would help. How did you adjust the full siphon drain?

 

[averagesteve]

Pictures of setup would help. How did you adjust the full siphon drain?

I'll get pictures if I have time tonight.. I adjusted it with a true union ball valve, could not find a gate valve anywhere. The overflow is quiet, just the return isn't when the pump is running near max.

 

[averagesteve]

I actually solved this. Pump running high made the pump section low enough where the little overflow from the refugium compartment was making a ton of bubbles that were getting sucked into the pump and making it loud. Upon adding more water and setting up the ato, the loudest part of the tank is currently the fans on the light which I can live with. The overflow and pump are so quiet I wasn't actually convinced it was turned on.