Overflow Gurgling

[Philster]

Hi everyone, there is something I just cant wrap my head around regarding overflows and gurgling. I have 2 one inch drains on my 100 gallon tank. My thinking was to use one as the main drain and the other as an emergency overflow. Right now I am using a strainer on the main drain (I have a 90 degree street elbow that I am not using at the moment). The emergency overflow sits just above the waterline. On the main drain is a gate valve.

I put 1/4 inch John Guest valves on the top of both end caps to act as air intakes. They sit about 5 inches above the water line. If I open the air valve on the main drain fully the water level rises up and begins to run into the emergency drain. When I slowly close it the water level comes down to just below the emergency drain but there is a lot of gurgling going on in the main drain.

My return pump is a Vectra M1 running about 1/2 speed or about 1000 gph. It has to rise about 4 feet in total and the return line has 1 45 elbow and 1 90 elbow.

Do I need to open the gate valve on the emergency line fully or use it to control the water flow through that drain? and what about the air valve on the main drain cap. Should that be fully open or closed? Sorry gang but I am struggling with this one and hope someone will be able to lend their expertise please. Thanks.

 

[thegrun]

Run a 1/4" air line from the John Guest fitting on top of the main drain line down to about 1/2" below the top of the emergency drain line but is higher than the Tee fitting on the main drain line. You want the open end of the air line to be under water when the return pump is running. Adjust the water level in the overflow box so that it allows just a trickle of water to run down the emergency drain line.

 

[Breadman03]

Look up "Herbie drain". It sounds like that is what you are trying to achieve.

Remember that an open channel drain will handle much less flow than a siphon drain. You are going to have to choose which you want to use on your main drain and adjust your return pump to a flow rate that will work with whichever you choose.

 

[mcgyvr]

Just like this (but you only have 1 not duals like this...)
http://www.reefcentral.com/forums/showthread.php?t=2595141

 

[Edz2891]

Check out the Maggie Muffler also.. It made my drain dead silent.

 

[Philster]

That video brought it all forward for me. Thank you for sharing that link.