Overflow mods and GPH numbers help

[zachrabbit15]

Hello everyone, looking to upgrade my current 90g to a 175. The tank has twin overflows, one in each corner. I want to convert the overflows to Herbie style, two keep the gurgling down, and use twin SeaSwirls on my returns. The stock Oceanic overflow is rated at 600GPH. By switching to the Herbie style can I gain any flow? Due to the unique aspects of the tank I want to stay away from drilling alot of holes, it would be very hard and expensive to replace the tank. So I need to controle water movement using wavemakers and the returns.

 

[user 26995]

I dont think you will increase the flow at all. The flow is determined pretty much by the size of the opening in the bulkhead, size of pipe or hose and any flow restrictions, like 90 degree elbows.

 

[kpiotrowski]

these numbers are pretty close... a 3/4 pipe with drain about 660gph straight syphon and 1 inch is about 1000gph.