Pump Selection

[ShipOFools]

need to decide on a pump for a 55 gallon with basement sump can be inline or submersable tank is 8' above sump any suggestions???

[N8ster]

You need to do two things:
1. Determine the total turnover you want, and how much of this you want to come from your return pump. Turnover is how many times per hour you move 55 gallons through your tank. The total targeted turnover should depend on what you want to have in the tank. The amount from your return pump may also depend on how much flow you expect to get from powerheads.
2. Calculate the amount of pressure you will need to get this flow, given the head loss on 8' of vertical flow. Go to the main Reef Central page and look for the head loss calculator on the left side of the page. You can change the pump selection until you get the flow you want.

[ShipOFools]

So if I have a Koralia 4 and 3 I can run a smaller return pump? since they count in turn over? what should I be targeting for a lps and sps tank 15X a hour?

[Aquarist007]

the flow should only be 5-10 times the total water column in gph through your sump and or match the outcome of your skimmer.

in the tank itself you are right

[Aquarist007]

You also have to remember that if it is a one inch gravity feed return to your sump then the max flow you are going to get is 600gph.
If you are running a single one inch return then you might get 700and change out of it--that's all.
I made the mistake of using a mag3600 for my setup which sounds very similar to the way you are going----I could have gotten away with a less powered and costly to run pump taking into consideration the physics of my return lines

[joe 09]

i like the mag drives pumps, they are energy efficent and easy to repair.you should use at least 11/4 inch pipe on the pump,because of the distance from the tank,this will reduce head loss.go with the mag drive 950 or 1200.this will give you 10 to 15x turn over.

[ShipOFools]

ok thanks

[Aquarist007]

Originally posted by joe 09
i like the mag drives pumps, they are energy efficent and easy to repair.you should use at least 11/4 inch pipe on the pump,because of the distance from the tank,this will reduce head loss.go with the mag drive 950 or 1200.this will give you 10 to 15x turn over.

I haven't been able to pin anyone down Joe--will the energy consumption crank down on these pumps if you curb the flow they are having to pump. At the full 3600 gph mine uses 360 watts per hour---that is not energy effecient--due to one inch piping the mag and bends ect , head pressure of 7 feet then the mag is probably pushing maybe half of less of that actually way less because the drain is one inch gravity feed and the sump and tank levels are in equilibrium.
Do these pumps also crank down on the power consumption?

[joe 09]

if you want to move that much water,you might want to look at the performance pro pumps.the 1/8 hp will move 3000 gal.at 161 watts,or the 1/8 hp 3500 at 205 watts.these are high head pumps and will pump that much water that far without loosing any head pressure.i have the 1/4 hp on my pond it pumps 4900 gal. 9 1/2 ft. up without loosing any pressure.

[Aquarist007]

Originally posted by joe 09
if you want to move that much water,you might want to look at the performance pro pumps.the 1/8 hp will move 3000 gal.at 161 watts,or the 1/8 hp 3500 at 205 watts.these are high head pumps and will pump that much water that far without loosing any head pressure.i have the 1/4 hp on my pond it pumps 4900 gal. 9 1/2 ft. up without loosing any pressure.

thanks Joe--but there is no point in my system of doing that--because of the diameter of the pvc the 3600mag is overkill itself in that system--it was a mistake from the first--but I am trying to make the best of it
This is why I asked you if a mag pump did less work, then did the wattage it draws also go down in proportion. I have not been able to find an answer to that.

[joe 09]

the pump will use the same amount of wattage,you would have to use a smaller pump.the md 3600 uses 380 watts,md 9.5 93 watts,md 12 110.if you are going to change pumps,go with the 1200,you are going to have head loss pumping water that far.also you should never restrict the input or suck side of the pump.do it on the output or push side.

[Aquarist007]

Originally posted by joe 09
the pump will use the same amount of wattage,you would have to use a smaller pump.the md 3600 uses 380 watts,md 9.5 93 watts,md 12 110.if you are going to change pumps,go with the 1200,you are going to have head loss pumping water that far.also you should never restrict the input or suck side of the pump.do it on the output or push side.

thank you Joe--your the first one that could give me a definitive answer on that
I understand that is the problem with all the mag pumps--that the wattage won't decrease with work the pump is doing. I believe blue lines or enheims do and would be a better solution??

[sjm817]

Sorry, that is not correct.

The pump uses less wattage when doing less work. Mag, Eheim QO, OR, whatever. It doesn't matter. If you want to prove this for yourself, spend ~ $25 and buy a Kill-A-Watt meter and measure it.

A Mag pump is not a great choice for a basement sump since it is a flow pump, not a pressure pump. for a basement pump, you are better off with an external that is meant for a high head application.

[joe 09]

i agree with the choice of pump, he should go with the external as stated earlier.but some of the external pumps are wattage hogs. sjm817 would you would save that much wattage with a pump doing less work.i thought the savings would be minimal.

[Aquarist007]

Originally posted by sjm817
Sorry, that is not correct.

The pump uses less wattage when doing less work. Mag, Eheim QO, OR, whatever. It doesn't matter. If you want to prove this for yourself, spend ~ $25 and buy a Kill-A-Watt meter and measure it.

A Mag pump is not a great choice for a basement sump since it is a flow pump, not a pressure pump. for a basement pump, you are better off with an external that is meant for a high head application.

That's a hard concept for me to grasp because I don't see where the pump would be doing less work---it still is trying to give the same constant output but working against greater head pressure

that's a great idea---for measuring alot of areas of consumption--I buy one today.

[sjm817]

Here is a test that AZDesertRat did on an Eheim 1260. Different pump, but the same idea applies:

Open discharge = 63 watts @782 GPH
1 psi (2.31 feet of head)= 60 watts @ 499 GPH
2 psi (4.6 feet of head) = 54 watts @ 433 GPH
3 psi (7 feet of head) = 50 watts @ 356 GPH
3.5 psi (8 feet of head) = 46 watts @ 300 GPH
4 psi (9.5 feet of head) = 43 watts @ 253 GPH

Mag36 is a monster of a submersible. I'd be curious to see what it is pulling for power use and what the GPH is.

[Aquarist007]

Originally posted by sjm817
Here is a test that AZDesertRat did on an Eheim 1260. Different pump, but the same idea applies:

Open discharge = 63 watts @782 GPH
1 psi (2.31 feet of head)= 60 watts @ 499 GPH
2 psi (4.6 feet of head) = 54 watts @ 433 GPH
3 psi (7 feet of head) = 50 watts @ 356 GPH
3.5 psi (8 feet of head) = 46 watts @ 300 GPH
4 psi (9.5 feet of head) = 43 watts @ 253 GPH

Mag36 is a monster of a submersible. I'd be curious to see what it is pulling for power use and what the GPH is.

great chart and thanks for posting it but i still don't understand the concept here
I don't see how the work of the pump decreases with head pressure. It still has to work as hard but just can't accomplish or push as much against the head pressure.

[AZDesertRat]

The pump really doesn't see pressure, it sees flow. If it were a positive displacement pump like a piston or progressive pump it would be a different story.
The same thing applies to a fan moving air, maybe air flow is easier to grasp? It kind of relates to slippage is an easy way to describe it I think.
Maybe dots can step in here and help with an explanation???

[dots]

The topic of throttling back a pump discharge came up a few weeks ago, it has to do with the Affinity laws that are used in pump theory. Below is what I had posted then along with the links for further reference.


http://www.pumped101.com/

http://www.pumped101.com/efficiency.pdf

http://www.motorsanddrives.com/cowern/motorterms8.html

http://www.driedger.ca/ce1_cp/CE1_CP.html

So I searched and searched for some good recources that would explain your question about power and pumps that was easy to read and straight forward with all the information related to our application. So rather than type and type and type it all.....you can read, and read and read it all.

Here is the deal, and the key are pump curves and knowing where you lie on that curve. One of the most confusing and misunderstood things that people do when setting up thier tank are the return pumps. Most of the time, the mistakes we make are so minor, it doesn't matter, however when you get into larger flows and pressures and larger pumps the problems of a mismatched system are evident, and costly. This is why we get away with ignoring pump curves and buying the pumps FIRST rather than designing the system. Instead we go about it backwards and wonder why we have so many "problems" Pump selection should be based on the required flow, with a given and prededermined Total Dynamic Head, that is based on the plumbing design. Most problems occur when this is ignored for personal observations of others, based on what is usually a different setup than what you will have.

The key to pump selection is finding a pump that operates at it peak effeciency based on your system conditions. If not, the pump will not preform at its peak flow, pressure, which may vibrate or cavitate. The relations between these characteristics in pump applications such as ours are governed by the Affinity Laws as seen in one of the links. There is such a law that relates power used as discussed here, but there is nothing for free and the efficiencies and pump performances are changed.

It is true, throttling the suction does decrease the amperage draw, but this also shifts the duty point of the pump, creating a less efficient pump, which in turn can lessen flow or TDH. The main concern with suction throttling is it effect the Net Positive Suction Head and the increase possibility of cavitation, (another misdiagnosed reefer problem that is usually air entrainment instead), if the pump was already poorly matched with the system, this can only compound the system.

The Affinity laws also relate to impeller diameters, which I am suprised is not played with more in the hobby, by trimming or increasing the diameter of the impeller one can bring the system and pump curves in line to match the two, which in turn relates to Variable Frequency Drives that could be thought in regards to as "infinitly adjustable impellers". VFD's are cool because the shift the Best Efficiency point (BEP) of the pump.

Well, I didn't write "that" much.......lots going on though and may not be worth the pennies you may save in doing so.

[Aquarist007]

Originally posted by dots
The topic of throttling back a pump discharge came up a few weeks ago, it has to do with the Affinity laws that are used in pump theory. Below is what I had posted then along with the links for further reference.


http://www.pumped101.com/

http://www.pumped101.com/efficiency.pdf

http://www.motorsanddrives.com/cowern/motorterms8.html

http://www.driedger.ca/ce1_cp/CE1_CP.html

So I searched and searched for some good recources that would explain your question about power and pumps that was easy to read and straight forward with all the information related to our application. So rather than type and type and type it all.....you can read, and read and read it all.

Here is the deal, and the key are pump curves and knowing where you lie on that curve. One of the most confusing and misunderstood things that people do when setting up thier tank are the return pumps. Most of the time, the mistakes we make are so minor, it doesn't matter, however when you get into larger flows and pressures and larger pumps the problems of a mismatched system are evident, and costly. This is why we get away with ignoring pump curves and buying the pumps FIRST rather than designing the system. Instead we go about it backwards and wonder why we have so many "problems" Pump selection should be based on the required flow, with a given and prededermined Total Dynamic Head, that is based on the plumbing design. Most problems occur when this is ignored for personal observations of others, based on what is usually a different setup than what you will have.

The key to pump selection is finding a pump that operates at it peak effeciency based on your system conditions. If not, the pump will not preform at its peak flow, pressure, which may vibrate or cavitate. The relations between these characteristics in pump applications such as ours are governed by the Affinity Laws as seen in one of the links. There is such a law that relates power used as discussed here, but there is nothing for free and the efficiencies and pump performances are changed.

It is true, throttling the suction does decrease the amperage draw, but this also shifts the duty point of the pump, creating a less efficient pump, which in turn can lessen flow or TDH. The main concern with suction throttling is it effect the Net Positive Suction Head and the increase possibility of cavitation, (another misdiagnosed reefer problem that is usually air entrainment instead), if the pump was already poorly matched with the system, this can only compound the system.

The Affinity laws also relate to impeller diameters, which I am suprised is not played with more in the hobby, by trimming or increasing the diameter of the impeller one can bring the system and pump curves in line to match the two, which in turn relates to Variable Frequency Drives that could be thought in regards to as "infinitly adjustable impellers". VFD's are cool because the shift the Best Efficiency point (BEP) of the pump.

Well, I didn't write "that" much.......lots going on though and may not be worth the pennies you may save in doing so.

thanks so much dots and az---I will take time later to read the links--certainly alot to comprehend--but I like the challenges this hobby brings