Tunze RO Water Controller


New member
I am planning to purchase this product


My plan is to fill a container with RO/DI water which will then be used to fill an ATO reservoir and also feed a mixing tank for making salt water.

I like this unit because it will allow me to use to float switches to tell the RO unit to fill this tank only when the water level reaches the lower sensor. Thus running my RO system once, until the tank is full, rather than in spurts constantly.

My question is, should I put the solenoid that shuts off water flow on the input like PRIOR to the RO/DI unit, so it cuts off flow entirely to the unit? Or should I put it in the output line between the RO/DI unit and the storage tank?

Additionally, I'm not clear on whether the RODI unit continues to process water and produce waste even if the output line is closed, or does it work only if it is open? I am using the BRS 4 stage 75gpd, which comes with an auto shutoff installed. But I am unclear on whether it shuts off the output, or does it shut off the entire unit?

I plan to plumb the line directly into my kitchen sink, so it has a constant source of water. Yes I am aware of the risks, and planning to build in multiple redundant safety measures to avoid flooding.

Thanks in advance.


New member
According to the directions on the Tunze site, the solenoid goes between the last pre-filter and the RO membrane.