Continuous Monitoring of Microbes

The only way I know of is by microscope with a camera connected to an image recognition computer.

Feed it all the shapes of potential microbes and let it "watch" the fluid at the point of the vector pump as it comes past. Set the field of depth at the middle of the flow tube and let it ring a loud bell and switch the vector pump off when it spots something.

Expensive way of doing it but safe. I never see them do this so I suppose they have a way and means to keep it free from microbes while the fluid is in the bag. Why not investigate that, seems cheaper and better?

What is your set-up here, just curious what you want to achieve?

When monitored automatically by camera, several shapes can be counted by sophisticated software. I know there is a reliable company in the US called "Data Translation" who sell so-called "frame grabbers" for such kind of environmental research. Their portfolio ranges from b/w to color, from low to high resolution and from slow to extremely fast, with the according monetary relations .... ;-)
Regards Uwe

There is no reliable way to do it. No offense to the comments posted. I have spent quite a bit of time in development of bio remediation. The number one issue with new technology is proving efficacy. If there was a way to "real time" measure microbes, we could do a better job of verifying technologies. There is one new device that works on genetic signals that looks interesting, but has yet to be proven in the field.

Look at ime inc. at imetest.com for the closest match I am aware of.

You might consider some way of monitoring the transparency of the solution. If that would be a valid indicator.