Flow Question/Concern with Jebao DC-9000

Derek4real · Oct 16, 2020

So, I bought some used equipment and have some questions about the return pump I have decided to use.
The tank is 72 X 24 X 17 Rimless tank with a center overflow (1" Bulkhead 960GPH, 3/4" Bulkhead 660GPH).

Here is the following equipment that I will be using,
(2) 3/4" SeaSwirls using 3/4" Loc-Line
Jebao DC-9000 (Bought USED)

So after doing some research, I found that the Jebao DC-9000 is 1.5" Inlet and Outlet, that is listed at NPT but is actually BSPT.
This pump according to the chart will flow approx. 1717gph, based on approx 4ft of head pressure. I'm guessing that is output at 1.5" and NOT being reduced.
So a unknown for me with this DC pump is I am unsure if this is the GPH at a reduced output. How do figure out what the GPH is on its lowest setting before plumbing it?

So I'm gonna have to eventually reduce it down to (2) 3/4" return for the SeaSwirls. So I will be going from the 1.5" PVC reduced to a 1" Tee X 3/4" X 3/4" to feed the two SeaSwirls. Doing some research the max flow through 3/4" hole is 660GPH. With the smallest inline reduction being 1" (flowing 960GPH), then being split to (2) 3/4" returns (960/2= 480 per 3/4" SeaSwirl) Is that an accurate calculation? With all these crunching of numbers my concern is, I am worried about having too big of a pump that can out run my drains.

I also have a Deltec Skimmer that needs a feed pump (450gph-475gph) and I was gonna tee it off the return pump to help with redirecting the back pressure from all the reducing I'm gonna have to do.

Ron Reefman · Oct 17, 2020

Reducing the size of the return plumbing from 1.5" to 1.0" isn't nearly the reduction if it were just a gravity drain plumbing.

Run a test moving water from one 5g bucket to another and measure the time. You can test it with the proper head height and pipe reduction as well.

The flow numbers you are looking at are for gravity fed pipe, not for flow from a pump.

You can turn down the flow rate on the pump.

I'd highly recommend you get a second pump to run just the skimmer. And you can do an open line from your return manifold, through a gate valve to the sump for reduction in flow to the tank.

Derek4real · Oct 17, 2020

Ron Reefman said:
You can turn down the flow rate on the pump.

Yes, I did some research and was curious to know what this pump flows on the lowest setting.< This thread > suggesting flow for this pump at the lowest setting 1400GPH but i am unsure how he came to this calculation.

Ron Reefman said:
I'd highly recommend you get a second pump to run just the skimmer. And you can do an open line from your return manifold, through a gate valve to the sump for reduction in flow to the tank.

Yes, I had originally planned for a separate feed pump. In the case that their was too much back pressure on the pump, I was suggesting to run the skimmer off the return pump to reduce the back pressure. I would like to have as little as possible or no back pressure on the pump, if possible. Another possibility would be to gravity feed the skimmer via the overflow box.

Saltyanimals · Aug 4, 2021

Derek4real said:
Yes, I did some research and was curious to know what this pump flows on the lowest setting.< This thread > suggesting flow for this pump at the lowest setting 1400GPH but i am unsure how he came to this calculation.

Yes, I had originally planned for a separate feed pump. In the case that their was too much back pressure on the pump, I was suggesting to run the skimmer off the return pump to reduce the back pressure. I would like to have as little as possible or no back pressure on the pump, if possible. Another possibility would be to gravity feed the skimmer via the overflow box.

Where did you get the max 660 for 3/4 from? I'm having the same internal debate for my own plumbing.