Please advise me a bulletproof ATO

[Clavius78]

For 10 years I used a DIY ATO that used two float switches. It activated a double power socket, so I could use whatever pump in my fresh water supply. And I used two pumps, so if one failed the other would still do the job. I'm not even that technically literate, I literally just followed an online tutorial back then. And during those 10 years it miraculously never failed. But I decided wise up and switch to something more safe after that...

• I tried the Hydor smart control with 3 tiny sensors. Looked really promising. For some reason it didn't detect my waterlevel accurately. I've had return pumps running dry. And also the ATO pump going on for way to long.
• I tried one with an optical sensor from Autoaqua. The optical sensor also seems inaccurate. I've had return pumps running dry. And also the ATO pump going on for way to long. After a few months the optical sensor proved that it wasn't even water proof and the unit failed completely.
• I tried a very similar device from DD, with very similar results. Only difference was the sensor leak before I discarded it.
• Currently I'm on to Tunze, with an optical sensor and a second float switch that checks for the ATO being on too long. So it has a double check to prevent overflowing. This would have been great if it also had an extra float switch that checks for dry running. Because you guessed it, I've had return pumps running dry.

All this has led me to trust old fashioned float switches 100x more then other types of sensors. If I was confident enough in my DIY builds then I would build a new ATO with 3 float switches, but I'm not. So long story short: One to keep the optimal level. A second one to prevent dry running. And a third one that prevents overflowing.

I would really want an ATO that just has 3 float switches. Does such a thing exist? (Or with other type of sensor, but 2 backup float switches.)

 

[reefing102]

I’m not aware of any system that has 3 float switches. Even my apex and Kamoer run dry. What I’ve done is found how quickly it depletes and try to refill it prior to it running dry (typically every 4 days)

 

[Clavius78]

I’m not aware of any system that has 3 float switches. Even my apex and Kamoer run dry. What I’ve done is found how quickly it depletes and try to refill it prior to it running dry (typically every 4 days)

I don't mean the fresh water canister running dry, but the sump space where the top off water gets pumped. The sensors seem to think my water is level and don't run the ATO pump. Therefore the level in the sump drops and my return pumps run dry.

 

[mellotang]

Put a quality float valve in sump
Elevate RODI storage water above sump
Run 1/4 line from RODI water to float

Gravity takes care of the flow
Not too much pressure in the line and minimal chance of float valve failure

No sensors
No failures
No smart features outsmarting you n not filling

Pretty easy

 

[kharmaguru]

For 10 years I used a DIY ATO that used two float switches. It activated a double power socket, so I could use whatever pump in my fresh water supply. And I used two pumps, so if one failed the other would still do the job. I'm not even that technically literate, I literally just followed an online tutorial back then. And during those 10 years it miraculously never failed. But I decided wise up and switch to something more safe after that...

• I tried the Hydor smart control with 3 tiny sensors. Looked really promising. For some reason it didn't detect my waterlevel accurately. I've had return pumps running dry. And also the ATO pump going on for way to long.
• I tried one with an optical sensor from Autoaqua. The optical sensor also seems inaccurate. I've had return pumps running dry. And also the ATO pump going on for way to long. After a few months the optical sensor proved that it wasn't even water proof and the unit failed completely.
• I tried a very similar device from DD, with very similar results. Only difference was the sensor leak before I discarded it.
• Currently I'm on to Tunze, with an optical sensor and a second float switch that checks for the ATO being on too long. So it has a double check to prevent overflowing. This would have been great if it also had an extra float switch that checks for dry running. Because you guessed it, I've had return pumps running dry.

All this has led me to trust old fashioned float switches 100x more then other types of sensors. If I was confident enough in my DIY builds then I would build a new ATO with 3 float switches, but I'm not. So long story short: One to keep the optimal level. A second one to prevent dry running. And a third one that prevents overflowing.

I would really want an ATO that just has 3 float switches. Does such a thing exist? (Or with other type of sensor, but 2 backup float switches.)

I don't mean the fresh water canister running dry, but the sump space where the top off water gets pumped. The sensors seem to think my water is level and don't run the ATO pump. Therefore the level in the sump drops and my return pumps run dry.

Do you happen to run an Apex? A reed (float switch) on a breakout box could be programmed to disengage the ATO if the return chamber gets to a certain level. However I think having this in the fresh water vat makes infinitely more sense. The pump will stop immediately instead of waiting for your return chamber to drop.

If you still have your original DIY system, you could use the float switches inverted (on in the up position) in your vats of concern and plug your current modern ATO into it. Your DIY would simply provide power for your ATO until the chamber(s) ran down to whatever point you set and the power to the ATO would be killed.

I've run the same DIY ATO for over 20yrs now without failure and it uses one reed switch. I don't really understand why manufacturers have shifted to optical sensors when reed switches have a super long track record of dependable performance in multiple applications. Some things should just remain analogue.

 

[kharmaguru]

I see XP aqua has a multi-sensor ATO but I would far from call it "bulletproof".

XPAQUA

 

[Timfish]

I like your DIY design with three float valves. But I've never seen a ATO design that doesn't have some issue sooner or later. As long as biology can interfere and equipment can fail ther'll be issues sooner or later.

 

[wildman926]

Put a quality float valve in sump
Elevate RODI storage water above sump
Run 1/4 line from RODI water to float

Gravity takes care of the flow
Not too much pressure in the line and minimal chance of float valve failure

No sensors
No failures
No smart features outsmarting you n not filling

Pretty easy

Exactly! You have to do your maintenance, i.e. clean the float valves but that is very rare. I do mine twice a year. Here is mine on the 150g, but they are old pics. I have the same setup on my 90g. Been running this for 11 years, and has failed when I did not clean the float valve. I have been needing to build a cabinet to match the tank to make it look nice.

 

[BeanAnimal]

I use a reservoir with a float valve in the sump.
There is a float switch in the sump set just above the HIGH water mark. This is a failsafe for the reservoir fill.

The reservoir is fed from the RO/DI unit and controlled via logic from my P4. Before the P4 the reservoir auto-fill was controlled via a latching relay circuit. The fail-safe float switch in the sump cuts this circuit off if the sump level gets too high (failed float valve or other issue).