Waterflow management

[RBS NEWBEE]

I am currently working on setting up a 125G reef tank. My return pump 1350 GPH and is variable speed but I was wondering how much water can 2 overflows with 2- 1" overflow lines handle? Technically there will be 4- 1" lines going into an 1 1/4" header. Do you think that will handle the 1350 GPH? Head height is about 3-4 ft. high.

 

[Andy Sager]

I am currently working on setting up a 125G reef tank. My return pump 1350 GPH and is variable speed but I was wondering how much water can 2 overflows with 2- 1" overflow lines handle? Technically there will be 4- 1" lines going into an 1 1/4" header. Do you think that will handle the 1350 GPH? Head height is about 3-4 ft. high.

In theory you shouldn't but here's the catch: flow rate for 1" pipe is 37 gpm while flow rate for 1 1/4" pipe is 62 gpm so two 1" pipes flowing into one 1 1/4" pipe will not flow more than 62 gpm. Converting this to GPH, that's 3,270 GPH. If it were me, I would not have more than one 1" pipe going into the 1 1/4" header. You don't gain anything by having both do that and you gain nothing by having the single header go into the double header. The flow rate of the one header does not increase because it's split later on. If you can, I'd let the 1" pipes just flow into your sump without any headers.

That all said, depending on what you want in the reef, your 1350 GPH return pump is probably too small for the 125. Watch/ read this: https://www.bulkreefsupply.com/cont...re answering,times your display tank's volume.

As for the flow rate at height, you need to check with the pump manufacturer as to how much flow rate is lost as the height increases. Not all pumps are the same. Some don't do heights at all.