i need to say, this is not mine! i actually posted it as i didnt want to lose the page :-/

For pump flow, i would use power draw as a proxy for flow. if the power is really low, it equates to a low flow. I already have them on Athom smart plugs, which have power monitoring. I actually use this to auto-prime my bore pump, which will turn on-off as needed to get the flow through. I'll post it at some point.

I have at atlas scientific wifi pool monitor which does auto-sampling but there is a bunch of maths and a lack of motivation/time to implement! one day maybe!