How to stop gurgling in my modified tank?

[pixelhustler]

I recently modified a IM 10g to keep small jellyfish and plumbed it down to the sump on my main tank.

I used the back panel of the AIO as the “overflow box” and drilled the back of the tank for the drain line. The problem is I’m getting an awful gurgling noise. I drilled the whole at the same level as the “slits” in the back panel - should I have drilled it lower?

I’m planning on drilling a second hole tonight for the return pump, as my original plan for a return didn’t provide enough flow. Should I drill the second hole much lower and use it for the drain instead and would this prevent gurgling?

(Restricting the flow on the return pump with a valve will also not work as the flow is already pretty low even for jellyfish.)

 

[Arego]

With it falling through a hole like that yes it's going to gurgle. Put a gate valve on that pipe to control how much water going down so it stops sucking right at the waterline and rather from under the waterline like you would normally down with the bottom drilled drain.

It won't matter where the hole is if it's setup wide open with a hole for the water to funnel through.

 

[pixelhustler]

With it falling through a hole like that yes it's going to gurgle. Put a gate valve on that pipe to control how much water going down so it stops sucking right at the waterline and rather from under the waterline like you would normally down with the bottom drilled.

I thought about it but I’m worried it might clog and cause a big flood since im using 1/2 vinyl pipe for the drain and it’s pulling from a large sump.

I’m drilling a second hole so I can use it for the drain instead - would drilling much lower than the water line stop the gurgling?

 

[Arego]

Try half way if the pump is strong enough it should cover that hole under the waterline while allowing no gurgle to occur because it's not air and water at the same time like your setup is now.

Is this drain in the return section of your aio?

 

[pixelhustler]

Try half way if the pump is strong enough it should cover that hole under the waterline while allowing no gurgle to occur because it's not air and water at the same time like your setup is now.

Does that make sense

I think so - anywhere below the “teeth” in the back panel should work, correct? I’ll go a couple of inches lower as a buffer just in case