Which Neptune Systems Flow Sensors?

[nickkohrn]

I want to install a Neptune Systems flow sensor in my return plumbing. I have a COR-15, which has a 1.25” outlet that is reduced to 1”. The return bulkhead at the tank is 1”, so I will have 1” PVC installed for the entirety of the run. I plan to have 400-600 GPH running through the return. Would the 1” or 2” flow sensor be best? The 1” model can handle all of the flow that I would put through it, but I want to ensure that the collected measurements from the sensor are as accurate as possible.

 

[rkpetersen]

I haven't used them myself, but I would think it best to use the one that fits your system. If you plumb in a larger one, it could introduce turbulence, cause inaccurate or erratic readings, and ultimately reduce flow. But that's all theoretical based on the situation you describe.

 

[TheHarold]

I dont understand why the 1" wouldn't be perfect. You have 1" plumbing, its within the range of the sensor, etc. The 2" one + adapters on either end would end up being pretty big too.

 

[nickkohrn]

I was hoping that the 1” would be the best option, but I wanted to ask because I’ve seen it mentioned in a few places that upsizing them would result in more accurate readings. It makes sense that the 1” model would be the best option, so that’s what I’ll use.

Thanks!

 

[Csr1978]

I was hoping that the 1” would be the best option, but I wanted to ask because I’ve seen it mentioned in a few places that upsizing them would result in more accurate readings. It makes sense that the 1” model would be the best option, so that’s what I’ll use.

Thanks!

Definitely use the 1". Fittings that change size will also reduce flow, due to resistance.

 

[SuncrestReef]

I agree on using the 1" in your situation. You should only use a larger flow meter in situations where you have an in-between pipe size. For example, if you had 1.25" pipes, you would use the 2" meter rather than reducing down to the 1" meter.

Be sure to place the flow meter in an area that's relatively easy to get to. Eventually you will need to remove it for cleaning.

 

[DCR]

I have heard that these APEX paddle wheel meters add a lot of head loss in the smaller sizes. Unless you are running a very high head pump, I would go with the 2". You are already pushing the limits of 1" piping at 600 gph. And if you are running a DC, then save yourself some power and go with a larger meter.

 

[Pazil]

I agree with above. 1" is best for this situation. I run the cor20 with the 1" flow monitor, works perfectly, just pay attention to the direction of flow... it matters!

 

[ca1ore]

Hard to say for certain since I have no experience with the COR pump, nor how much ‘extra’ pump capacity you have. I have used all the sensors, and do find that the 1” sensor puts quite a bit of friction pressure on the pump as the internal dimensions reduce a bit from standard 1” ID plus paddle ‘drag’. On the other hand, the FS200 is physically very large. Probably if your goal is 400-600 gph the FS100 will work. Either sensor will give you reasonably accurate readings.

 

[robbyg]

I have heard that these APEX paddle wheel meters add a lot of head loss in the smaller sizes. Unless you are running a very high head pump, I would go with the 2". You are already pushing the limits of 1" piping at 600 gph. And if you are running a DC, then save yourself some power and go with a larger meter.

I Just wanted to correct one of these myths.
An 1" pipe can push through about 2200 GPH at maximum. In real world aquarium usage you will probably get about 1600 GPH with most pumps on the market. Of course lots of variables in that one but the 1" pipe on my aquarium is doing 1200 GPH with a Reeflo Dart when she is turned up full.

 

[DCR]

I Just wanted to correct one of these myths.
An 1" pipe can push through about 2200 GPH at maximum. In real world aquarium usage you will probably get about 1600 GPH with most pumps on the market. Of course lots of variables in that one but the 1" pipe on my aquarium is doing 1200 GPH with a Reeflo Dart when she is turned up full.

Agreed it can be done, but it is not an economical choice. Your Dart is putting up 11-12 ft of head at 1200 gph according to their curves.

Most people are not using pumps that powerful. ​

Assuming you have 4 ft of elevation gain, you are running 7-8 ft of frictional head loss. That is a lot of head loss. I think a target head loss of 2-3 feet is much more appropriate. The pressure drop goes up with the square of the flow so at 1600 gph, you would need almost 20 ft of head at 1600 gph. At 2200 gph, it will be close to 30 ft. There is no practical maximum - depends how much pump head you want to supply and how much power you are willing to consume.

I do hydraulics as an engineer for chemical plants and I can tell you no one would select a 1" line for 1200 gph. It is not an economical choice when considering power consumption and the cost of an increased line size. You can push these limits in an aquarium to some extent due to the relatively short runs, but it pains me to see people spending 100's of dollars on expensive DC pumps for efficiency and then use undersized return lines that negate much of the potential savings. In reality, I believe most reefers simply overestimate how much flow they really have.

 

[robbyg]

Agreed it can be done, but it is not an economical choice. Your Dart is putting up 11-12 ft of head at 1200 gph according to their curves.
Most people are not using pumps that powerful.
Assuming you have 4 ft of elevation gain, you are running 7-8 ft of frictional head loss. That is a lot of head loss. I think a target head loss of 2-3 feet is much more appropriate. The pressure drop goes up with the square of the flow so at 1600 gph, you would need almost 20 ft of head at 1600 gph. At 2200 gph, it will be close to 30 ft. There is no practical maximum - depends how much pump head you want to supply and how much power you are willing to consume.

I do hydraulics as an engineer for chemical plants and I can tell you no one would select a 1" line for 1200 gph. It is not an economical choice when considering power consumption and the cost of an increased line size. You can push these limits in an aquarium to some extent due to the relatively short runs, but it pains me to see people spending 100's of dollars on expensive DC pumps for efficiency and then use undersized return lines that negate much of the potential savings. In reality, I believe most reefers simply overestimate how much flow they really have.

While i agree with some aspects of your post I will tell you that my plumbing is going up 6ft and is fed into a 4 way diverter that is actually the cause of much of my water flow loss. Not that any of it matters because the problem I also face is that I am using a KLIR DI-4 rollermat and therefore I have to cut down the flow to 740 GPH so that the KLIR can handle the flow. The part about your statement I kind of disagree with is the power consumption. My pump at 1200 GPH vs even 740 GPH is not using a heck of a lot more current. I measured it once with a Killawatt meter and it was only a small difference. Now admittedly I have never tried this with a DC return pump but I suspect that there is not going to be some huge jump in power consumption.

Update: I just did some reading to see what kind of power consumption curve DC pumps have VS head pressure. People are saying that there is no real increase in power consumption with AC or DC pumps vs the amount of Head pressure. I know it sounds counter intuitive but that was also my observation.

 

[DCR]

While i agree with some aspects of your post I will tell you that my plumbing is going up 6ft and is fed into a 4 way diverter that is actually the cause of much of my water flow loss. Not that any of it matters because the problem I also face is that I am using a KLIR DI-4 rollermat and therefore I have to cut down the flow to 740 GPH so that the KLIR can handle the flow. The part about your statement I kind of disagree with is the power consumption. My pump at 1200 GPH vs even 740 GPH is not using a heck of a lot more current. I measured it once with a Killawatt meter and it was only a small difference. Now admittedly I have never tried this with a DC return pump but I suspect that there is not going to be some huge jump in power consumption.

Update: I just did some reading to see what kind of power consumption curve DC pumps have VS head pressure. People are saying that there is no real increase in power consumption with AC or DC pumps vs the amount of Head pressure. I know it sounds counter intuitive but that was also my observation.

Frictional losses in hydraulic systems equate to power loss. You are putting heat into the fluid via friction. I know from previous posts that you understand electrical systems well, and it is the same as high resistance creating voltage drop and heat. For a water system, you can actually calculate the theoretical additional power consumption in watts by multiply the flow rate in gph times the head loss in feet, times 0.00314. So with 1000 gph losing 6 ft of head equates to about 19 watts. Since most pumps are only about 50% efficient, the additional pumping power requriement would be about double that. Reducing your head requirement will reduce your power demand if you select the right pump.

Now I agree that once you select an AC pump like yours, you are more or less locked into a power draw regardless of where you operate on the curve (how much head), but you could have chosen a smaller pump with less head and less power if your piping was enlarged. A DC pump changes the head/flow curve so you can increase or decrease the speed to match your pump to the resistance of your piping. The power draw of the pump will certainly change with speed (which affects the head), although where you operate on the curve at a fixed speed may not have much effect.

 

[robbyg]

Frictional losses in hydraulic systems equate to power loss. You are putting heat into the fluid via friction. I know from previous posts that you understand electrical systems well, and it is the same as high resistance creating voltage drop and heat. For a water system, you can actually calculate the theoretical additional power consumption in watts by multiply the flow rate in gph times the head loss in feet, times 0.00314. So with 1000 gph losing 6 ft of head equates to about 19 watts. Since most pumps are only about 50% efficient, the additional pumping power requriement would be about double that. Reducing your head requirement will reduce your power demand if you select the right pump.

Now I agree that once you select an AC pump like yours, you are more or less locked into a power draw regardless of where you operate on the curve (how much head), but you could have chosen a smaller pump with less head and less power if your piping was enlarged. A DC pump changes the head/flow curve so you can increase or decrease the speed to match your pump to the resistance of your piping. The power draw of the pump will certainly change with speed (which affects the head), although where you operate on the curve at a fixed speed may not have much effect.

We are pretty much on the same page. I am always inclined to go bigger with the pump than I really need to and I think most people are doing that also. Today is a little different because as you say you can vary the DC pumps output and save a few watts if you minimize the head pressure. I will admit to you that I am just not a fan of DC pumps. While I do recognize some of the benefits, I am very weary of the failure rate. If you buy a Red Dragon or Abyzz pumps you can get very reliable long term service but I just cannot see myself spending a couple of thousand dollars on pumps.

I am still puzzled by some posters claim that they see less wattage being used when the head pressure was increased. One guy goes as far as to say that turning his return off used the least amount of power! My experience was just a slight increase not a decrease.

Wow i just realized we really hijacked the Ops post, but it has been a good discussion. If you have an idea on why the above statements could be true please let me know.

 

[fattiremike]

For what its worth, I push 700 gph through a one-inch flow meter with a sine-wave DCP 15000 Jaboe pump.

 

[DCR]

We are pretty much on the same page. I am always inclined to go bigger with the pump than I really need to and I think most people are doing that also. Today is a little different because as you say you can vary the DC pumps output and save a few watts if you minimize the head pressure. I will admit to you that I am just not a fan of DC pumps. While I do recognize some of the benefits, I am very weary of the failure rate. If you buy a Red Dragon or Abyzz pumps you can get very reliable long term service but I just cannot see myself spending a couple of thousand dollars on pumps.

I am still puzzled by some posters claim that they see less wattage being used when the head pressure was increased. One guy goes as far as to say that turning his return off used the least amount of power! My experience was just a slight increase not a decrease.

Wow i just realized we really hijacked the Ops post, but it has been a good discussion. If you have an idea on why the above statements could be true please let me know.

I am in agreement with you on DC pumps. While they do offer great flexibility and efficiency, I share your concerns on cost and reliability.

For a radial flow pump operating at constant speed, the power requirement will go down as you reduce the flow rate and increase the head. Blocked discharge will give you minimum power. The following link to a family of pump curves of a line of small industrial mag drive Teflon lined pumps that I frequently use. Each curve is for a different impeller diameter and the numbers on the curves are the pump efficiency. You can see from the second plot how the hydraulic power is reduced. That is only for the pump, so you would also have to factor in how the motor efficiency would change with load.

http://www.innomag.com/index.php/a1-1-5x1x6-3500

For an axial flow pump (like a Vortech propeller pump), the situation is reversed and the power consumption goes up when you reduce the flow and increase the head. Some pumps are a combination of radial and mixed flow and they tend to be more constant power throughout the curve.

 

[DCR]

For what its worth, I push 700 gph through a one-inch flow meter with a sine-wave DCP 15000 Jaboe pump.

That is also a pretty large pump (4000 gph) for only 700 gph. Nothing wrong with it, but I would maintain you could reduce your power consumption with a larger meter.

Not sure what speed you operate at. ​

 

[ca1ore]

I am still puzzled by some posters claim that they see less wattage being used when the head pressure was increased.

Pretty well established actually .....

How Pumps and Motors are Affected by Cycle Stop Valves – Cycle Stop Valves, Inc

Back Pressure Increasing backpressure does not make pumps work harder. One horsepower is the measure of power it takes to lift 33,000 pounds of weight one foot in one minute. Gallons and weight are the same thing to a pump. Restricting the flow from the pump with a valve, backpressure will...

cyclestopvalves.com

 

[ckalupa]

I use the 1” on a COR15