Head height question for DC pumps

[Richard Hercher]

This is a total noob question: Does adjusting dc control on a rerun pump change the head height? I’m planning out a basement sump and since I got a shiney new Apex, so of course I’m thinking about a COR-20. I’m not ruling out a big Jaebo or a Panworld if I go AC.

The big concern I have is head pressure. My math with bends puts the system with a head height at about 13ft of height. I like the idea of the Cor-20, being able to tune it while I’m upstairs watching the tank. If I lower the flow of a DC pump, does the pump loose head height?

 

[lapin]

http://www.nesc.wvu.edu/pdf/DW/publications/ontap/tech_brief/TB55_PumpCurves.pdf

yes

 

[Richard Hercher]

http://www.nesc.wvu.edu/pdf/DW/publications/ontap/tech_brief/TB55_PumpCurves.pdf

yes

K. Thanks for the answer! Unfortunately, there was nothing in that document that discusses power variability, just diameter of the impeller (which I’m assuming is not variable).

 

[lapin]

Sorry.
I saw the curves and though they explained it.
There are curves for rpm/current vs head height.

 

[Bob Lauson]

If you look at the head flow curve for this pump is shown below which comes from Neptune. The max flow you will get at around 13 feet head will be around 400 GPH

 

[Bob Lauson]

The pump will follow the head flow curve and the one Neptune gives is at 80w of power consumption. As you dial back the pump rpm, the curve will be lower at all points. So yes, if you have 13 fat of head loss than at some speeds less than full speed you will run out of head and the pump won’t pump.

 

[siggy]

What size tank? I have a little Giant ac pond pump in the basement mix-sta, it says a 21' head but a 12' rise and 18' of hose I get about a gallon a minute maybe 2.

 

[slojim]

basement sumps seem pretty cool to me, now that I live in an area without basements. But you pay for it in power and pump sizing to lift the water back up. If I ever move back to a basement-friendly area, I think I'd still try to keep my sump right under my tank, with provisions in the basement for water transfer/water changes. I know this isn't your question, but since you are in the planning stages, I thought you might not mind.

 

[Mar344]

I am planning a basement sump and feel that DC pumps just don't have the head height. They aren't designed to pump water that high. I am going with a pan world 250ps. I feel it offers the best flow after head loss at a reasonable efficiency.

 

[Richard Hercher]

The pump will follow the head flow curve ...

Right. I’m not a math whiz but I do know my way around a calculator. I just wish I remembered enough high school physics to shift it: is it a linear or geometric change? If I cut it by 8W (10%), do I lose 2 feet of max head pressure as well as 40gph? Or Is there some kind of square law where cutting 10% of power results in a 50% loss in head height, unless you constrict the pipe diameter (so, scratch that earlier statement, some level of college physics I didn’t take).
Thanks man!

 

[Richard Hercher]

basement sumps seem pretty cool to me...

Thanks for engaging! I appreciate the conversation. For me, the dream is the big basement sump with nice show Refugium and manifold. Right now my Rodi and mixing station are down there, and there’s a bunch of room, and I want that to be my “fish room”—my 8yo kid wants to be a marine biologist today (who knows what next week will bring) but we’ve been talking about making that room “the science lab” for 3 years.
The tank is just a 75g With a canister now, but the stand Has no space for a sump of any size (I can’t even get the canister I want to fit in). So new tank (something 6ft long, not sure how deep or tall yet) to replace it is on the list for the next 2-3 years, but I figure I can get started on the Sump sooner

 

[Richard Hercher]

I am planning a basement sump and feel that DC pumps just don't have the head height. ...

I hear you. I’m not in the Abyzz budget, but for me, I do audiobook recording in my basement (far side) and a submersible pump is the best bet for reduced noise.

 

[Mar344]

I hear you. I’m not in the Abyzz budget, but for me, I do audiobook recording in my basement (far side) and a submersible pump is the best bet for reduced noise.

I did look into the red dragon pumps. Don't remember the specs. But they might be worth a look. Much more affordable than the abyzz.

 

[slojim]

In that case, flow is proportional to rpm, head is proportional to rpm squared, and power is proportional to rpm cubed. You can probably get your answer searching the web for "pump affinity laws"
Enjoy the basement lab with your child, sounds well worth a few extra dollars on pumping.

 

[siggy]

A few @ReefSquad run basment sumps, @Flippers4pups I think has one. These are the guys you want to learn from.

 

[Falco]

I run a basement filter room setup on my system and I use a Cor-20 for both my returns (I have 2 display tanks). The display that is on my main level has about 15ft of head pressure and at full power I am getting about 350gph (clocked with a 1" apex flow meter). I was originally hoping for more but I have 2 WAV pumps in the display and I am ok with the turn over rate of the tank. I am also running a Cor-20 on my 2nd display which is only at standard setup height (its in the filter room) and that is reading 620gph fully open.

with that all said I really like how quiet the DC pumps are. I have a pan world pump that I use for my mixing station and it is not only much louder but also gives off a decent amount of vibration (even sitting on a dampening pad) to the point where I just picked up another cor20 that I am going to drop in the saltwater vat for when the mix is complete and I will run that at like 50% to keep the water moving around and heated. I will also have that for a spare return pump (that justified the purchase in my head, lol).

 

[Bob Lauson]

I also have a basement sump which I love. I use a Turbo-Sea 1740P Coralife pump (same as the Pan World NH200PS) which has 39 ft of head and 1740 GPH @ 0 ft. My system has about 20 ft of head loss and i measured the flow in my 180 gallon display tank at close to 900 GPH. This aligns pretty well to the pump's head-curve.

 

[Mar344]

I also have a basement sump which I love. I use a Turbo-Sea 1740P Coralife pump (same as the Pan World NH200PS) which has 39 ft of head and 1740 GPH @ 0 ft. My system has about 20 ft of head loss and i measured the flow in my 180 gallon display tank at close to 900 GPH. This aligns pretty well to the pump's head-curve.

What diameter pipe are you running?

 

[ca1ore]

This is a total noob question: Does adjusting dc control on a rerun pump change the head height?

Not really ….. sort of. The max head height for any pump is the height at which the pump at full power will stop moving water. Setting a DC pump at an output lower than full power will reduce the amount of flow at a particular height below that max level.

 

[ca1ore]

I am planning a basement sump and feel that DC pumps just don't have the head height. They aren't designed to pump water that high. I am going with a pan world 250ps. I feel it offers the best flow after head loss at a reasonable efficiency.

Most DC pumps are configured for flow rather than pressure, though I think the speedy pumps have an impeller/volute replacement to better handle pressure. I run a basement sump room and concluded the same, that the DC pumps were not up to the task. I now run a panworld 250 that works well, if a bit nosily …. but its in the basement.