Gravity-fed Osmolator ATO?

[DLHDesign]

I've got a Red Sea 525XL and have replaced the ATO tank with a direct connection from my RO/DI reservoir; plumbed into the existing float switch. The reservoir is higher than the sump, so I don't have (need) a pump to get the water from one tank to the other. My fuge re-enters my sump right below the float, however, and I'm worried that a piece of chaeto or the like (or just buildup over time) could result in a stuck switch. I've got a mechanical "kill switch" on the incoming line, so I'm not worried about an overflow, but I'd also like to avoid adding too much RO/DI to the DT while I'm on a trip (because we all know this is when it would happen).

I like the idea of the Tunze Osmolator, but I'm not really sure how to plumb it in given that I don't need a pump. What I think I need is an "normally closed" solenoid of some kind that the Osmolator could trigger open when water was needed.
I thought about using the Tunze RO Water Controller, but that operates off two float switches - so I'd just be trading one problem for two. The solenoid I need is part of that kit, however, so I think what I'm looking for is a kind of hybrid of the two...

Suggestions?

 

[jsker]

Hey
I had the same issue when I went to a sump. The sump was lower than my ATO Reservoir and when the pump would shout down i would get a siphon. Instead reinventing everything I just moved the fill line back to the tank and the problem was solved. Just a FYI, having the RO/DI setup like that burns through DI and the membrane faster or I would leave my RO/DI on to the ATO Reservoir.

 

[DLHDesign]

Pumping into the DT would work; yeah - good call!

Note that I'm not hooking the line directly to the RO/DI setup - I have a ~50gal reservoir for "clean" water that I have my ATO line hooked into. I also pull from it when I need to make new saltwater (I don't have a system set up for automatic water changes - yet...).