Neptune Aquatics

Solenoid for RODI .. bad idea?

Oh I know all that. I have well water with high TDS so we use a lot of RO water. Having a larger, pressurized RO tank means less TDS creep because you’re making RO water in larger amounts. And some will auto flush the membrane before they refill the tank.

The ideal scenario would be to run the RO unit at night after flushing. Let it fill the tank and that’s the water for the next day.
 
For what it’s worth in my setup I have the Tunze water controller filling up a 5g Home Depot bucket that I’m using as the RO container. It starts refilling when it gets down to about 1g left, and finishes when it’s about 4g full, so approximately 3g per fill. Then the Tunze ATO tops off the tank with that water. I didn’t want to go smaller than that since we are trying to minimize the TDS creep issue, but you certainly could go larger like Omar said.

The Tunze water controller comes with the float switches for high and low levels, as well as the electronic failsafe to turn off if it’s been on for too long. As another fail safe, I also add a regular RO float switch shut off where the water line from the RODI comes in to the bucket (drilled) near the top, just above the level where it should have already shut off.
 
JVU said:
For what it’s worth in my setup I have the Tunze water controller filling up a 5g Home Depot bucket that I’m using as the RO container. It starts refilling when it gets down to about 1g left, and finishes when it’s about 4g full, so approximately 3g per fill. Then the Tunze ATO tops off the tank with that water. I didn’t want to go smaller than that since we are trying to minimize the TDS creep issue, but you certainly could go larger like Omar said.

The Tunze water controller comes with the float switches for high and low levels, as well as the electronic failsafe to turn off if it’s been on for too long. As another fail safe, I also add a regular RO float switch shut off where the water line from the RODI comes in to the bucket (drilled) near the top, just above the level where it should have already shut off.
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I use a Neptune ATK. Add an additional optical sensor for the bottom and a solenoid.
Both optical sensors in the float valve bracket are used to close the solenoid, Top most is failsafe. Float is mechanical failsafe.
Bottom optical sensor is used to open the solenoid.

RODI unit is from Spectrapure, it has an auto flush so I don't have to do that manually.

Even if you have an automatic fill or if you do a larger volume vs just topping off directly, if you are not flushing before start (and preferably after end), you will still get TDS creep.
 
I ended with the following semi automated setup. RODI plumb directly to the ATO reservoir. Control by the solenoid (optical sensor) and old fashion float switch. Optical sensor is placed below the float, so float is acting as the fail safe. I also added the Flowlok leak detector just in case.

Setup the solenoid to activate only when i select "Fill Mode" on the Hydros Control App. Fill mode have 15mins timer. Either 15mins is up or the optical sensor activate.

After making coffee in the morning, which will flush the RO, i can enable the filling from the app. Its not fully automatic but better than what I have now.
 
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JVU said:
Your morning coffee is taking one for the team!
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Haha.. no i let the water run for 20s or so . TDS is ~300 in the first cup of water, then drop really fast to ~10 range.

I have a split on the RO output. One to the sink drinking water, then other line get DI filter to the tank.
 
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