Water output per day monitor?

[GarrettT]

I have two containers

-RO Water (ATO)
-Kalk (on a doser)

I would like to find a monitor that measures the fluid output per day. This way if my RO water's output is unusually high, I know the Kalk doser isn't working. Does a monitor like this exist? I see Neptune has a FMM module, but I believe that only measures the flow rate and not the actual fluid amount.

 

[Quietman]

BRS sells a filter monitor with volumizer (look on RO Monitors). It's not tied into any controllers just a metered output to read.

I'm sure there's similar devices offered by filter companies.