Sral
Valuable Member
Just to answer @Wolfw28 's question somewhere where other people can find it more easily:
About the flow meters:
They should be accurate to about 10% out of the box, if you inserted the tabled calibration factor. Mine from Adafruit for example has one of 5.0 (I think). If you want more accuracy you need to calibrate it like you mentioned: capture the flow with all piping and height differences in a bucket and weigh/measure that.
About the pump:
Flow value:
The given flow values are usually idealized without any load, e.g. water straight from a tank into another tank without any pipe resistance or height difference. As soon as you connect pipes, introduce bends into those pipes or install filters, that goes down. For a freshwater aquarium with a filter you can usually expect the flow to be half the specified value or less. That goes down with time as you get biological films on all the pipe surfaces.
Pump height:
That is, I think, the maximum height the pump can manage, e.g. exactly the height, where the flow of the pump goes to zero. If we assume a linear dependency, which might not be entirely true, 1m lift of 3m Max should reduce flow by another 33%.
In total that makes:
50%*66% = 33%
So if your Setup is comparable to a freshwater aquarium filter you should have about 1/3 of the pump specified max flow or lower.
Something to keep in mind though:
The required lift might be lower than you think, if the water’s gravity also pushes into the pump. That cancels out some of the required lift. For my freshwater aquarium for example, the inlet is effectively at water level. Afterwards the water stays contained in a pipe through the pump and filter, without any contact to outside air and pressure, and re-enters the aquarium at the outlet about 2cm above water level. That means my lift height is actually 2cm, even though my pump and filter are 1m below the aquarium. Not sure how that works in a reef-aquarium, but you can send me photos of all the parts and we can work it out if you are unsure.
About the flow meters:
They should be accurate to about 10% out of the box, if you inserted the tabled calibration factor. Mine from Adafruit for example has one of 5.0 (I think). If you want more accuracy you need to calibrate it like you mentioned: capture the flow with all piping and height differences in a bucket and weigh/measure that.
About the pump:
Flow value:
The given flow values are usually idealized without any load, e.g. water straight from a tank into another tank without any pipe resistance or height difference. As soon as you connect pipes, introduce bends into those pipes or install filters, that goes down. For a freshwater aquarium with a filter you can usually expect the flow to be half the specified value or less. That goes down with time as you get biological films on all the pipe surfaces.
Pump height:
That is, I think, the maximum height the pump can manage, e.g. exactly the height, where the flow of the pump goes to zero. If we assume a linear dependency, which might not be entirely true, 1m lift of 3m Max should reduce flow by another 33%.
In total that makes:
50%*66% = 33%
So if your Setup is comparable to a freshwater aquarium filter you should have about 1/3 of the pump specified max flow or lower.
Something to keep in mind though:
The required lift might be lower than you think, if the water’s gravity also pushes into the pump. That cancels out some of the required lift. For my freshwater aquarium for example, the inlet is effectively at water level. Afterwards the water stays contained in a pipe through the pump and filter, without any contact to outside air and pressure, and re-enters the aquarium at the outlet about 2cm above water level. That means my lift height is actually 2cm, even though my pump and filter are 1m below the aquarium. Not sure how that works in a reef-aquarium, but you can send me photos of all the parts and we can work it out if you are unsure.
