Flushing waterfarms with controller setup

How do you go about flushing your plants on a controller + waterfarm setup? I am gonna get a controller but want to know if there is a special way to flush the waterfarms without having to disconnect them and flush them individually. I currently have them seperate from each other and have been flushing each ones hydroton and rinsing out the reservoirs in the bath tub. But now that I'm wanting to use a controller.... obviously if I try to rinse each one seperately, I would have to disconnect the hoses to the reservoirs which seems not the right way without making a mess. Any of you waterfarm + controller setup types please chime in and let me know. Thanks!

As far as I know about the recirculating system, I would think you would pump everything into the reservoir and take it to dump the old nutes. Put the res back and then hand water/flush each individual W/F. The water will equalize anyway and then pump it back into the res and dump as needed to finish the flush. You could install valves in any hoses you need to disconnect to keep from spilling everywhere.

Just empty the water via the controller and pour in new water.

Is there a shutoff valve between the controller and the farms that prevents back flow of nutes into the controller when you need to disconnect the controller to empty?

No, there shouldn't be. You want the nutes that are in the buckets to be drained too. Otherwise how would you be doing a flush?