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foxt
08/18/2016, 10:07 AM
Apologies if this has been asked and answered (I searched, but didn't find anything): what kind of real-world performance might I expect from a RD3 230W at 15' of head? The pump curve shows a knee in the curve at around 4m of head, going on a straight line from 1840gph at 4m to 0gph at 6.8m. Reading off of the curve, it looks like it might show about 1300gph at about 5m of head? Can anyone with real world experience report on the flow with a RD3 230w on a basement sump with about 15' of head ?

slief
08/18/2016, 11:37 AM
I would expect at least 1300GPH and probably closer to 1500 GPH. If I were running one with that kind of head height, I would oversize the plumbing all the way to the display to reduce friction loss. The RD3 230 has a 1.5" output and I would step that up to 2" immediately after the the pump all the way to the display. That should help things a bit. Especially given that you are also going to have fittings such as elbows and or valves between the pump and display that will also factor into head loss. The larger diameter pipe and fittings will reduce head pressure caused by those fittings.

foxt
08/18/2016, 01:05 PM
Thank you very much for the response. I am feeding two 1" sea swirls on the DT with the return, and I also plan to try the Triton method, so I need lots of flow (the guideline is 10x DT volume, so 2400gph). I might decide to run two independent pumps from the basement to the DT, and it seems like two RD3 230W's would be able to supply 2400gph if I go that route.

Two return pumps get me into other issues though, such as having one pump fail or shut down and start to siphon the DT back into the basement sump while the other pump is still running. I was hoping for one submersible pump large enough to supply the target flow, but my options are proving to be limited ...

slief
08/18/2016, 01:38 PM
Thank you very much for the response. I am feeding two 1" sea swirls on the DT with the return, and I also plan to try the Triton method, so I need lots of flow (the guideline is 10x DT volume, so 2400gph). I might decide to run two independent pumps from the basement to the DT, and it seems like two RD3 230W's would be able to supply 2400gph if I go that route.

Two return pumps get me into other issues though, such as having one pump fail or shut down and start to siphon the DT back into the basement sump while the other pump is still running. I was hoping for one submersible pump large enough to supply the target flow, but my options are proving to be limited ...

If you sump is large enough and the returns are high enough and near the surface of the water, the siphoning shouldn't be an issue as the tank level will drop slightly and the 2nd return would be out of the water to prevent the siphon.

Having said that, I don't run the triton method but I have seen the 10x through the sump debated a bit. Typically 10x turnover through the sump is on the high side though it also won't hurt anything. The idea is that the higher flow helps with the macro algae and nutrient export since in theory the algae will see more nutrients from the higher flow.

foxt
08/18/2016, 02:46 PM
Thanks again. Triton will be new for me, as will 10x through the sump. I figure if I can get close enough, so be it. but at 1300gph I would be at about half of what I need, so I want to try to get closer. I have to consider a single external pump vs. two RD3 230W's. If I am allowed to say this here, at the cost of buying and operating (2) RD3 230W's, I am getting into Abyzz A400 territory so there is that to think about as well.

I like everything I have read about Red Dragon though, and the one advantage I can see of this option is that I could actually run the system at a fairly high flow rate and see how it behaves before deciding to accept the cost of the extra flow by buying the second pump.

Lots to think about .... thanks for the information.

Tim
08/19/2016, 09:09 PM
I'm in exactly the same position planning my 450 with basement sump please let me know what you decide foxt and how it works out.

Ps I'll be at MACNA in SD doing research hope to see the options frist hand

foxt
08/19/2016, 10:00 PM
I'm in exactly the same position planning my 450 with basement sump please let me know what you decide foxt and how it works out.

Ps I'll be at MACNA in SD doing research hope to see the options frist hand

I would be interested in your thoughts after MACNA....

Breadman03
08/20/2016, 12:07 AM
I've been running a RD3-230 on my 150 with basement sump for about 6 months or so. I'm at 73% with pretty solid flow. It doesn't flow as much as the Blueline 70 it replaced, but it does it with quite a bit less wattage and WAY less noise.

If I turn off my pump, my tank drains down about 1/2-3/4 of an inch due to the placement of my returns. I could make that less than 1/4 inch if I was to trim my return plumbing closer to the surface.