Choosing correct flow rate for chlorine dosing or metering pump

jwfrank

Bronze Supporter
LifeTime Supporter
Oct 14, 2008
58
Todi, Umbria, Italy
I posted this on a Stenner thread. I will try a new “generic” thread. basically my question is: should I choose a flow rate for a back pressure higher than what the pool filter shows? Would it reduce the run time of the dosing pump because the flow rate is higher? I am buying a replacement solenoid dosing pump for liquid chlorine injection. From years of experience, I know that I regularly use between 1 liter and 1.25 liters PER DAY to keep my free chlorine level at 2-3ppm which is fine for my pool. My question has to do with the SIZING of the dosing pump. My circulation pump runs 8 hours per day in 4 intervals. My old dosing pump runs on a timer which is activated when the circulation pump turns on . I control the amount of chlorine added by how long I have the dosing pump running, usually 1 to 2 minutes for each circulation pump interval. My question is which of the following models would be best to choose as a replacement. The 0110 model is closest to what I am replacing but since the circulation pump and filter operates at a low bar (under 2 or 30 psi), I am wondering whether the 0607 might be better suited. The dosing pump models shown can be adjusted to lower the “strokes” which would reduce the amount injected per “run”. (PS I live in Italy and hence the liters/hour etc.). I know that most of the models shown (on the left side of the graph) would work, but which would be best? Many thanks for your advice

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Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
23,598
SouthWest Alabama
Let's work with what you gave us.
You say the pressure is 2 barg or less so the 0110 pump will pump about 2½ l/h at 2barg.

To get to the worse case scenario of 1½ liters, you'll need to run the pump 38 minutes total to inject the required amount of bleach into the system. Since you normally run the main pump for 8 hours you'll have plenty of time to get the bleach injected during the normal run time of the main pump with the 0110 injection pump.

Now for the 0607 pump. It can inject 7.3 l/h at 2barg. For the same scenario you'd need to run this injection pump for 12 minutes total.

Either pump will inject enough bleach into the system within the main pump run time, so it's really which you're more comfortable with.