True Pump Flow Rate vs the Rating

[twinclouds]

I have a 4500 gallon pond with two waterfalls (2' high). It is mainly for water lilies and some gold fish. At beginning, the contractor installed two Aquascape Pro 4500 pumps. They works fine but consume a lot of electricity. Since All of the koi were taken by herons. After a while, I only have some gold fish left and I don't think they are as demanding as koi. When the Pro 4500 stopped working, I was looking for some more energy efficient efficient pumps. I replaced one of them with Aquascape Pro 3000. It has a lower flow rate but looks o.k. Then the second pump connected to the larger portion of the pond died. I bought a Pondmaster Proline Hy-Drive 4800. However, it looks to me that the flow rate is almost the same as the Pro 3000. Recently, the Pro 3000 also died. I bought a Aquasurge 5000 to replace. However, the Aquasurge is only slightly better than Hy-Drive 4800. I was not happy about it so I decide to get a slight larger pump and using the Hi-Drive as back up. I bought a Matala VersiFlow V3900. It certainly consume more power than the Aquasurge and Hy-Drive (400w vs 250-280w) but seems only generating slightly larger flow and no where close to the Pro 4500. Does anybody have similar experiences?
The only difference I can see between Pro4500 and others are higher maximum head height. My question is: are there any better or power efficient pumps that can generate similar water flow as the Aquascape Pro 4500? I don't mind to buy another one and use the VersiFlow as back up but I don't want to risk buying another one that still doesn't have good water flow. Otherwise, I will probably just buy another Pro 4500 when become necessary.
Thanks in advance for anyone who can help.

 

[DoDad]

You may want to compare these two and their price.

Aquascape PRO
Pump Performance
Model: 4500
Rate Flow (GPH): 4500
Watts: 625
Volts: 120
Max Amps: 5.4
Operating Cost: $45.60/mo.
Vertical Shut-off: 33'
Horsepower: 1/4
Sug. Pipe Diameter: 2"

Model Sequence 4200SEQ12
Inlet 2"
Discharge 1.5"
Max Flow (gph) 4200
Max Head (feet) 12'
Max Power (Watts) 160
Max Current (amps)1.56
@ (volts) 115 115
Motor HP 1/8 1/8

 

[twinclouds]

Model Sequence 4200SEQ12 is an external pump but skimmer is using submerged pump. Not sure what type of modification will be needed to change to external ones. Probably I am rather not to. Thanks for your reply anyway.
My real interest if to find out why there are so much differences in true water flow for the pumps has similar rating. Wish somebody can provide some insight.

 

[DoDad]

Have you looked at WellSpring Submersible Pumps?
1/3hp 4.0amps max head 27 ft max flow 4458 @ 3 ft mid point flow 2700 gph @ 14 ft

 

[koikeepr]

DoDad is right on here. The power consumption alone will save you a heap! You don't need another pump on your skimmer if it's gravity fed to your pump. I don't have a pump in my filter...works on just gravity.

 

[twinclouds]

DoDad: Thanks for your suggestion. It looks good. Do you have first hand experience with it? My pump right now is a horizontal one but I don't see too much difficulty to convert to the vertical form, as long as its height can fit in..
Koikeepr: Not sure what do you mean by "if it's gravity fed to your pump." Do you have a pump? If you do, where is it if you don't have a pump in your skimmer.
Thank you both for your advice.

 

[koikeepr]

I have the sequence 4500 in question, yes! (great pump!). Since it's an external, I obviously don't have it in my skimmer. My skimmer gravity feeds to my pump directly. Meaning, I have it under water level so it can receive water via gravity flow.

Not sure if that makes any more sense?!

 

[twinclouds]

Now I understand. Thanks.

 

[D&RW]

I have a flow meter designed for a 2 in pipe. You have to drill a hole to use it. Afterwards you just cut out that section and put in a replacement piece.

I was really happy to use this because it gave me a fairly exact reading. The reason this meter was very important to me was to ensure that the flow through the UV filter wasn't excessive. Also, it was just kind of neat to be able to compare calculated flow vs. real flow. There's a website that has all kinds of predone spreadsheets for calculations. Most of the ones I've used are pretty close. http://garden-pond-filters.com/calculators.htm

If you want to borrow it I'll be happy to send it to you if you pay the shipping. If you do I'll also send you the bit to drill the hole because it takes a bit bigger than usual and they are expensive.

 

[twinclouds]

I have a flow meter designed for a 2 in pipe. You have to drill a hole to use it. Afterwards you just cut out that section and put in a replacement piece.

I was really happy to use this because it gave me a fairly exact reading. The reason this meter was very important to me was to ensure that the flow through the UV filter wasn't excessive. Also, it was just kind of neat to be able to compare calculated flow vs. real flow. There's a website that has all kinds of predone spreadsheets for calculations. Most of the ones I've used are pretty close. http://garden-pond-filters.com/calculators.htm

If you want to borrow it I'll be happy to send it to you if you pay the shipping. If you do I'll also send you the bit to drill the hole because it takes a bit bigger than usual and they are expensive.

Hi, D&RW:
Thank you for your information and generous offer for help. I am interested but I would like to know a little bit more about the meeter and the way how the measurement can be done first. Can you point me to where to find the information (Google directions?)? Where should I drill the hole and how to plug it afterwards?
BTW I am armature in water gardening but since I am an engineer, I just want to know exactly what is happening.
Thanks again.

 

[DoDad]

Most pumps flow rates are measured at the outlet after that it's all down hill.:bouncycig:

 

[twinclouds]

Most pumps flow rates are measured at the outlet after that it's all down hill.:bouncycig:

But flow rate (gph) should be the same anywhere along the path, right? I think you can measure it at the input, anywhere in the pipe or at the outlet. Looks like D&RW measures it at the pipe because he mentioned the meter is for 2 in pipe.

 

[DoDad]

Yes you can measure it anywhere. When you ad pipes and angled fittings and height the flow rate changes .So if the flow rate was checked at the outlet and it was 4200gph and you added pipe and fittings and height it may read 3600gph.
copied from a website.

Why do you need a pump in the first place? Well, you may not need one at all depending on what you plan to keep in your pond. But, if you plan to keep fish, particularly koi, in your pond, you may need a pump to both move the water over a waterfall or through a fountain for aeration, and to move the water through a filter to help keep the water clear and healthy for your fish.
A pump circulates water against the resistance caused by gravity and friction. The pump has to overcome gravity to raise the water above the pond's surface -- the higher the water is pumped, the more resistance the pump will face, and the less water will be delivered per minute. The resistance to water flow caused by gravity is measured in feet and is called the static head of the circulation system. The static head is measured from the surface of the pond (or other water source) up to the height to which the water is eventually pumped (the top of a waterfall, for example.) The static head does not change whether the water is coming from a bottom drain or from a surface skimmer; it's the pond's surface that matters, not the placement of the inlet.

The friction of the water moving through pipes also causes resistance to flow. A small diameter pipe causes more friction than the same length of a larger pipe, and the resistance increases as the flow rate increases. Because the resistance due to friction is not constant at all flow rates, it is called dynamic head. The dynamic head is also measured in feet (this may seem strange since it has nothing to do with height or gravity, but it's convenient to use the same units for both forms of resistance so that they can be combined and compared easily.) Dynamic head is also increased by changes in direction (such as elbow joints or curves in flexible tubing) and by any constriction of the plumbing system. Things like valves, pressurized filters, and pipe unions can all increase dynamic head.

The total resistance to flow caused by gravity and friction combined is called the total dynamic head and, since it includes the dynamic head as a component, it increases as the flow rate increases. The total dynamic head (TDH) is the total resistance a pump will face when delivering a given rate of flow. In general, a given pump's flow rate will decrease as the TDH rises. This relationship between TDH and flow rate defines the "power curve" of a pump. Many pump manufacturers even publish graphs of head versus flow rate to help customers choose an appropriate pump for their application. But, using these graphs requires that you know the TDH for your proposed system. How do you compute the TDH for your circulation system?

But flow rate (gph) should be the same anywhere along the path, right? I think you can measure it at the input, anywhere in the pipe or at the outlet. Looks like D&RW measures it at the pipe because he mentioned the meter is for 2 in pipe.

 

[twinclouds]

Thanks.

 

[twinclouds]

O.K., Now I understand you are talking about. You are concerning the flow rate that can be achieved by a pump. It will depend on the overall water way is constructed. I was talking about once a pond has been constructed and the pipes are in place, what is the flow rate can be achieved by different pumps. But thanks anyway.
BTW, The PerformancePro WellSpring pump looks attactive. It has a high head height. Have you ever used it?