too much kalk

[mr_alberta]

Usually that's the case unfortunately. What I've seen is some people drilling out the hole on the float valve to make it slightly larger to prevent the frequent plugging. However, you run the risk of the valve not sealing anymore....

[TheReefGeek]

A bit off topic, but with your float valve on your reservoir, do you have a hydraulic switch plumbed into your RODI to cut off the waste water production when the pressure in the feed line increases due to the float valve closing? Otherwise you will be producing waste water continually.

I have found these hydraulic switches to be sketchy too, they don't always work if you dont have a pressure bladder, depending on the distance between the feed line from the RODI and the float valve, the closer they are the better.

I have found float switches controlling a sprinkler solenoid (available at the hardware store) right at the tap feeding the RODI unit to be more dependable. This way the float switch cuts off all water getting to the RODI at all, and you dont rely on the hydraulic switch to cut off waste water production.