Detect the turbidity

On a good day, you can measure the turbidity using an Arduino, a LED, a phototransistor, and a resistor.

The problem normally has more to do with how to keep the optical window clean.(*) That might be easier with a clothes washer, because the flow is pretty strong and frequently has a lot of detergent and bubbles, which should help.

It'll need some experimenting, though.

How high-tech is your setup? I assume you have a storage tank, but how does the water get in and out, and how is that controlled?

Cheers

Phil Hobbs

(*) If you have the time, and a nearby library can get a copy, Mark Johnson's "Photodetection and Measurement" is an excellent read. Mark was the head of quality assurance for a bit water utility in England, and really knows turbidity measurements. A lot of it is quite accessible at hobbyist level.