Reservoir for ATO, but why?

[Rugbyfish]

Ok, I have never setup an ATO, but as I am doing my reading, I hear people advise to have the ATO to run from a Reservoir instead of straight for the ROI unit. Now I have been thinking about this and can’t figure out why. I understand that by having ROI feed right into the sump through the ATO, you would not be using the ROI correctly since the run times will be really short. And I can also see that if your ROI unit fails, you would start dumping in unfiltered water right into the sump as well. Are these the only reasons?

 

My real concern is what happens if my ATO fails to shut off and it keeps filling up the sump into overflow. The reservoir won’t help me in this scenario, right? I mean, the ROI unit would just keep filling up the reservoir and the reservoir would keep filling up the sump. Am I missing something?

 

Thank you,

Rug

[dsoz]

I don't have an ATO system. I do it the old fashioned way, by hand every day.

 

from what I understand, you don't connect the RO/DI directly to the resevoir. Fill the resivoir when needed, but then YOU have control over that process, not something that will break down.

 

Then at most you will dump X gal of RO/DI water into your system instead of an unlimited amount.

 

dsoz

[snowpunk]

I don't have an ATO system. I do it the old fashioned way, by hand every day.

 

from what I understand, you don't connect the RO/DI directly to the resevoir. Fill the resivoir when needed, but then YOU have control over that process, not something that will break down.

 

Then at most you will dump X gal of RO/DI water into your system instead of an unlimited amount.

 

dsoz

 

you can though, I think that is how franks system is set up. Runs directly from the DI unit into the sump and it's controlled by the float valve.

[madmike]

The reason people dont run directly from the RO/DI unit is the first little bit of water produced from the unit has a much higher TDS. Take a reading immediately when you start the unit and you will be shocked how high it is. If you add directy to the sump from the unit, you will be turning the unit on and off and so on, adding higher than normal TDS water. In a well designed system, the resevoir would only fill when it gets low, so you minimize the high TDS water by filling a resevoir when needed.... the larger the resevoir, the less times the RO/DI unit has to turn on and off.

HTH

 

The key to ATO is to have redundant systems in place like float switchs or pressure switches that turn the system off if it senses a failure from the water being too high.

[Nyles]

I have had my ATO for over 3 years now, its been rock solid reliable but I still pull from a reservoir (15% the tank size). There are times you will forget to turn off the ATO when working on the tank (water changes) and if the float fails (and it will) you only want so much water going in there so the effects wont be lethal. There would be nothing worse than having your skimmer go nuts because your neighbor is spraying his house with paint and your ro/di turns your saltwater tank to a cichlid feeder tank.

[Nyles]

Another reason is I mix kalk in my reservoir for added calcium, I could not do that with a constant fluctuation in the kalk / ro/di top off.

[Smann]

I have my ro/di unit on a selenoid and timer, it comes on once a day for 1 hr and keeps a 5 gal bucket full. I then use a powerhead to a float valve in my sump to pump thru the night. I'm not sure but I dont think you would want to create back pressure to the ro/di unit if you are going to use a float valve to prevent overfilling. also some people like to buffer and aereate their top off water before adding to the tank, I used to aereate when I used a larger can but I dont with a 5 gal bucket

[Rugbyfish]

I have enjoyed reading everyone's take on this concern.

Thank you,

Rug

[JManrow]

I should mention that an Tsunami AT1 AutomaticTopOff donated from Champion Lighting will be one of the Raffle Items at our June 6th Meeting.(rock2)