Water Flow Sensor ?

dino21

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Joined
17 Mar 2020
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91
Location
Derbyshire
Hi,

Has anyone used one of the many little inline water flow sensors you can see on Ebay and the like ?

Interested to know how much they are likely to impede the water flow on our Eheim Ecco ?

Need to set up an alarm as someone forgot to turn the pumps ( eheim + a surface skimmer) back on !

Any other simple way to detect flow ?
 

noodlesuk

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21 Jul 2020
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129
Location
Oxfordshire
Haven't tried a flow sensor, but will obviously reduce flow to some extent, which could change over time.

Could you detect pressure instead of flow? That should not affect the output flow rate. Depends on the back pressure in the line when running.

Pressure Switch

More complex but you could detect if the pumps were running by monitoring power use, via a current loop device.
 

Nick potts

Member
Joined
25 Sep 2014
Messages
269
If it is only to ensure the plug gets turned back on I would just pick up a smart plug. Plug in the filter and anything else and then when doing maintenance just set it to come back on in 20 mins or whatever.
 

chrisfraser05

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Joined
12 Jun 2010
Messages
404
As nick says I'd use smart outlets and monitor the current.

If the wattage dropps below a certain amount for a certain length of time have an alert setup.
 

zozo

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16 Apr 2015
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7,474
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Netherlands
I've seen those little flow sensors and i never could figure out where to connect them too. You would need some additional electronics and software that interprets the signal it gives to determine flow or alert when it is 0.

But anyway anything with an impeller inline will get dirty over time and it's just an extra piece that can fail, clog and restrict what it should be measuring. :)

Any other sensor to digitally detect flow in a closed system is a tad too professional and expensive for hobby purpose, I guess.

Tho if it's for a sump setup then it could be simple with a floater switch connected to a beeper or buzzer. If there is 0 flow, the water level in the tank lowers and in the sump, it will rise, either way, this can be detected with a floater switch.
 

Nick potts

Member
Joined
25 Sep 2014
Messages
269
Yes, get a bucket of known volume and see how long it takes to fill it from your filter outlet. Then do the arithmetic to determine flow rate.

Cheers,

Good for determining the flow of a pump occasionally, but not much use to activate an alarm if the flow stops etc
 

ceg4048

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11 Jul 2007
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8,993
Location
Chicago, USA
Good for determining the flow of a pump occasionally, but not much use to activate an alarm if the flow stops etc
Yes, you're right mate. I missed the bit about the alarm. It might be better to monitor the pump circuit as you mentioned. Lots of sturdy and reliable equipment available for that.

Cheers,
 

tiger15

Member
Joined
14 Mar 2018
Messages
510
Location
USA
The simplest DIY flow indicator is to tie a cotton thread at the end of the flow return. You can tie threads at regular intervals on a dip stick and move around to monitor flow distribution throughout the tank volume.
 

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