Flowrate through the corner overflows
 

I have a standard Marineland 180 gallon with two of the corner overflows. Per your documentation online, each overflow is listed at 700 to 750 gallons per hour.

I have a question. Is that flowrate of 750 gph based upon a single durso drain going through a 1 inch bulkhead or is it the maximum amount of water that can move through the actual openings available on the overflow itself?

The reason that I'm asking is that I was going to replace the durso with a full siphon drain. With an 8 foot drop to my sump, a 1 inch pipe, and a full siphon, I could conservatively move at least 2,000 gph. I was curious if the openings on the overflows themselves could handle that volume of water.

I'm thinking the openings on the overflow are the limiting factor. Did you ever get anymore info or a response from marineland on this?

I never did get a response from Marineland and unfortunately haven't been able to get more details from another source. I agree and do believe that it's likely the openings/teeth in the overflow that are the actual limiting factor.

Would have been nice to hear from Marineland to confirm that though before I finalize my plumbing plans for this 180 gallon build.

I have a 300DD and with two pumps, pumping around 1500 GPH, that maxes out my overflows.

When you run that rate is the water level touching the braces across the top of the tank?
Thanks

Thank you for the information. It helps. I do have a question. Are you running traditional durso drains in each of your overflows or something else?

The opening are the huge limiting factors. I have a 180 gallon dual over flow and I'm pushing about 2000 gallon a hour threw my return pumps. I had to break the plumbing tabs out of the over flow box to get more flow. I have my return lines from above and the over flows each have a emergency on each side. Idk if this helps

Thanks. That does help. It's good to have a confirmation as to where the flow is bottlenecking.

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