Increase drain flow

[haninja]

If you have been following my build you know I'm setting up a 180g with the standard mega-flo drains that are rated for 600 GPH each. The return pump is a barracuda sitting in the basement about 10' under the tank which, based on the pump's graph, is pushing about 2500 GPH. The symptom I'm experiencing is the water goes up and down in the overflow and makes noisy gurgling sound from the drains. Also down at the sump there are a lot of bobbles coming down the overflow. That is on full blast, when I throttle back the pump I get to a nice steady quite flow but I want to be able to utilize as much as I can in terms of flow.
Any modifications I can do to increase the flow? Any benefit to making my own dursos?

 

[mockery]

Well unless you drill more holes your going to be limited due to the bulkhead size.

 

[skriz]

What size are the bulkheads for the overflows?

 

[skriz]

Do you have ball valves on the drain lines at the sump?

 

[haninja]

I believe the bulkheads are 1", that is the standard size. There are no bulb valve on the drains only on the return.
What is the hole size on the 180? maybe I can put bigger bulkheads.

 

[smoothie]

I think standard is 1" drain and 3/4 return. Have you thought about using a smaller pressure rated pump instead, and using the barracuda for the closed loop? Just a thought.

 

[purplegorilla]

Like Mockery said. Gurgling means there isn't enough air in the drain. It is causing a suction. Just drill the hole larger until it goes away.

 

[weaglereefer]

The water going up and down in the overflow means a siphon is being created, which means you're not letting enough air in. Make the holes a little bigger.

 

[jonboyb]

Spot on. My return was putting an estimated 650-670 gph back to my tank with a single 1" return and Marineland standpipe (they rate at 700 but who knows) and I was having gurgling and surging of the overflow level. Based on comments I recieved, I enlarged the hole very slightly and it was an immediate fix. Although I think I'm probably right at the max return for a 1" bulkhead.

 

[haninja]

Smoothie;454985 wrote: I think standard is 1" drain and 3/4 return. Have you thought about using a smaller pressure rated pump instead, and using the barracuda for the closed loop? Just a thought.

Well, if I throttle it down then I can still use it fine, just wanted to get more of it.

purpleGORILLA;454989 wrote: Like Mockery said. Gurgling means there isn't enough air in the drain. It is causing a suction. Just drill the hole larger until it goes away.

au01st;454991 wrote: The water going up and down in the overflow means a siphon is being created, which means you're not letting enough air in. Make the holes a little bigger.

Yes, that was my thought as well. I will try this when I get home.