measuring water flow rate with controller


New member
Hi there folks, looking for some advice!

I would like to convert an existing lanthanum injection system to use canister style filters versus a filter sock. Currently the lanthanum is injected into a dedicated skimmer and the output goes to a filter sock with a float in it to turn everything off when it clogs.

The challenge is how to detect the filters in the canisters are clogging so that the lanthanum injection can be turned off. My concern is the lanthanum continuing to inject after the filters are clogged which will lead to (1) dosing pump and supply pump dueling it out due to pressure not he water line (2) possibly damaged pumps (3) possible build up of lanthanum in the line.

The current thought is to measure the flow rate out of the canisters and to turn things off when the flow drops too low.


...............Lanth Dosing pump
....................| 1/4" valve
supply pump -> T for lath -----------> 20 micron sediment filter -> 10 micron sediment filter -> flow meter -> output



New member
You can run your output (with the filter) into a bucket that has a U tube overflow into your sump. Put a level switch in the bucket and you have a volume counter.

If you use an Apex or other controller, you can use a 'hold on/high' function so a single event will be sustained for enough time to meet the next pulse and create a continuous 'on' signal to the skimmer.

If the flow rate is below the threshold in the 'hold on/high', it'll go off/low. You can use a long 'hold off/low' function to stay low for a long time & turn off the skimmer.


New member
I'm doing the same but for the opposite reason. I'm running my effluent into the bucket and using a doser to expel it at a controlled rate. If the effluent is so fast that it fills the bucket and overflows into the sump, then I get a 'high flow' warning.