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ATO Question

ok, so got a 2nd ATO for Christmas (from myslef) to use in my RO/DI reservior. So when water evaporates from my display tank and the water level drops in the sump my ATO will activate the solenoid valve and dual aqualifters will pull water from my RO/DI reservior and push it through the kalk reactor into topping off the sump. When the water is drawn from the RO/DI reservior and the level drops the ATO will activate the second solenoid valve opening the way for RO/DI to top off the reservior. before adding the ATO to the RO/DI reservior, i would wait until the RO/DI reservior was about 25% full then turn on the RO/DI to top off the reservior, a couple times I forgot the shut off the RO/DI and a couple of mini floods- thus prompting me to get the 2nd ATO. So, I just finished setting this up, and this question dawned on me- why not just the output of the RO/DI filter to the solenoid just before the kalk reactor. this way when the ATO in the sump is activated, the solenoid valve will open and fresh RO/DI will come through the filter into the kalk reactor and top off the sump. This would eliminate the need for the RO/DI reservior, the Aqua Lifters, and the need for a 2nd ATO & solenoid for the RO/DI reservior. i hope you understand what i mean, kinda hard to explain. what would be the drawback to eliminating the RO/DI reservior and having the RO/DI filter feed directly into the kalk reactor with a solenoid valve as a shut off?
 
vangvace said:
Yes a few drawbacks:

1. Better chance of flooding if the ATO gets stuck on fill.
2. TDS creep from short cycling your RO unit.

http://www.utahreefs.com/forum/forum_posts.asp?TID=1770&PN=1 is an old, but good thread from my former club. The first two pages of the four are the most relevant.

i see no greater risk of flooding, the RODI filter is connected to a solenoid now for the reservoir top off, would be the same thing if connected to the solenoid to top off the sump (through the kalk reactor)

what do you mean short cycling your RO unit?

also, btw, there are timers involved in the current set up- a timer on the ATO for the sump that activates the aqua lifters and the solenoid. this runs 4am-12am. the kalk reactor mixer runs 1am-3am. the ATO for the RODI reservoir is set to run for 15 minutes (shortest possible setting for timer) four times a day. this is to prevent the ATO/solenoid valce from going on/off all day as water evaporates from the sump/reservoir.
 
I also run a kalk reactor.top off water is kept in 35 gal container with a float switch which turns the ro/di unit off when it is full. ato is jbj works great
 
thanks for your input vangvace!

kinda suprised by the lack of feedbackfor this topic, was hoping to get some educated reponses

i think i have decided to carry on as i did before adding the second ATO and only turn on the RODI once a week (or so) for a few hours to fill the reservoir. the ATO will act as a failsafe. i dont feel safe enough leaving the RO/DI unit on all the time with just the solenoid preventing a massive flood.
 
Short cycling refers to turning your RO unit on for short periods of time. Using your RO unit to directly fill a drinking glass or a float valve constantly topping off a tank are good examples of short cycling. The way RO units are designed the first bit of water out of the membrane is the worst purity when the unit turns on.

I had more typed but then you replied again. :) If you plan on going this route in the future I would copy the design in the link I provided and add some snail guards.
 
thanks, makes sense. i am just going to continue as i always have in filling my RO/DI reservoir and the 2nd ATO will be 'just in case' i forget to shut the RODI unit off again when filling the reservoir. this way when i turn the RO/DI unit on i can let the first couple gallons go into a bucket for disposal, then start filling the reservoir.

i have snail gaurd on both ATO's (sump & RODI reservoir), but there are no snails in either.

one other concern that i had was that the waste water drainage from my RODI runs out a basement window and drains down my driveway into the street, i am concerned about this line freezing up in the winter. another reason why i wouldnt want the RO/DI activated by the ATO/solenoid. This way if i start it manually i can make sure the waste water is draining properly.
 
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