Reasons you need two ATOs...

[Sk8r]

One for your tank.
One for your qt. And yes, you can sterilize them. Just a light soak in bleach neutralized by an application of Prime.

What is an ATO? That's an autotopoff unit. It doesn't require a controller, just a simple float switch or pressure tube, a bucket, and a pump. If you have a stony reef that arrangement can double as a coral calcium supplementer---or kalk feed.

First of all, tank ATO is a must, if you want a nice stable tank and healthy fish and corals. While the ocean may locally fluctuate in salinity, fish there can vote with their fins and seek more comfortable levels. Fish in your tank are rather stuck. So be nice. Stabilize their environment.

Secondly, as regards your qt tank---you have fish that are already stressed. This is supposed to be a rest, not a physical trial. But even more importantly, if you are dosing ANYTHING, the dosage strength (or over-dose or under-dose) is all determined by how much water is diluting it. If evaporation happens, you are overdosing, allowing the fish to get MORE medication than he is supposed to, and some meds like copper are damaging at higher concentrations. If you add too much water, you are diluting the dose, and the fish isn't getting enough med.

And if you are doing hypo treatment, every time that water evaporates down to a higher salinity, you are helping ich survive.

To do these things successfully, you either need to check that water level multiple times a day or have a good sensitive ATO taking care of it. And the ATO will dose by teaspoons, not cupfuls, maintaining a much more even level.

[heathlindner25]

Don't believe they are a must....my acros can't tell that I'm pouring in fresh water in the morning& evening.

[billdogg]

Originally Posted by heathlindner25

Don't believe they are a must....

For a rare change, I agree with the above.

Sorry Sk8r! I can't remember the last time (if ever) that I've disagreed with you

I'm not about to say that they are not a good idea, but after 30 years without, I have to believe that there are other ways, especially for tanks big enough where a gallon or two makes no significant difference one way or the other. They are undoubtedly of more potential importance on smaller systems, but at the same time, failure of the ATO can mean bigger problems.

ATO's can fail. Not often, perhaps, but they can. When they do, it can be catastrophic for the tank, the floor, etc.

I do have my top off plumbed to the tank, but it is on a remote control so that I can control the amount. I will admit that even that way, it (I) can mess up. But I'll be there when it happens can can take immediate action to limit the damage.

[Sk8r]

Never had a failure. I've forgotten my ro/di fill way too many times, but never, ever had an ATO jam, never a whisper of a problem. I do use sealed dual float switches or pressure tube types---I have snails in the sump, but never a problem yet.
I do think it's a good idea. In a system that evaporates slowly, including some canopied qt's, not so much of a problem. But having the med level climbing up and down in a treatment or hypo tank, not a good thing.

But I don't argue, either, with people having success doing differently.

[splix]

I dont think an ATO is 100% necessary, but it will reduce your tank maintenance as well as keep things stable. I'm still new to reef'ing but thats my take on them. I dont have one yet, but I will shortly.

[joshbrookkate]

What type of float switches do you use? I am getting ready to set up an auto water change system with my Apex and I want good float switches.

[joshbrookkate]

And I just bought another ATO for my QT. So thanks for the validation that it is a good practice not an extravagance.

[firemountain]

I originally went some time without an ATO on my permanent QT. Then I booked and extended vacation for 2 weeks....this is where the ATO and fish feeder we're invaluable.

I personally wouldn't run a QT without one going forward,

[hogfanreefer]

I think the point about hyposalinity in a QT is spot on. If there is a place it's necessary that's it. I'm sure it's possible to be very successful without one in the DT as shown by the posters above but if there was one piece of equipment that I would not do without it would be my ATO.

[Bent]

I need to ATO my QT. That thing looses water quick. It's annoying.

[Sk8r]

The ATO I'm currently using on the main tank is a little Avast tube number, attached and adjustable by an exterior magnet, which if you don't have, say, a five year old who wants to adjust it, a very nice arrangment. If you do, I'd go for something more child-proof.

[Sk8r]

And be it noted, never fear: Bill and I can always disagree without disagreeability. He's right because he has a system that works well. In all these posts, do consider your individual situation, eg, got a larger qt than most, take the information IN the advice and fit it to your situation. What creates the problem, and has your system another means to avert it? If so, adjust to fit.

[KingTriton1]

ATO is a must for me.

[cloak]

I don't think they are a must either. Your obviously taking the time to feed your fish at least once a day. How hard is it to pour in a little freshwater until the water level matches up with the piece of scotch tape on the glass again. They're definitely a nice tool to have though.

[sbash]

Do you see any issues with dripping the QT and the main system from the same reservoir? It would be easy enough to add a "T" onto my ATO and a float valve onto my QT. How likely is the cross contamination in this scenario?

[MjKonesky]

not a must but an 'awesome'. i finally broke and bought a tunze ATO a couple months ago. best thing i ever did for my main tank. not sure about other skimmers, but mine gets angry when the water level isnt exact. i was having to top off a half gallon twice a day before i got an ATO and how its just a matter of filling the top off reservoir. if you can figure out how much evap loss you get per day then a drip would be amazing. there is no issue dripping the QT and the main, because there is no possibility of pulling water into the reservoir if you drip. solid plan as long as you can gauge your loss. also, you will most likely have different losses as the year goes on. so check through the seasons.

[BlackTip]

ATO are not a must. Reefers did without it for so long. It has its many advantages, however. The most important ones are stability of salinity and PH, if kalk is used. Also, it reduces the manual maintenance. I have a 25g reservoir that lasts about 2 weeks. I spend maybe 1/2 an hour every 2 weeks to fill it and dose it with kalk, and I am done for 2 full weeks. If I were to do it manually, I'd have to add 1/2 g of water 3 times a day X 14 days.....no thanks.

My QT tanks are small, 20g and don't evaporate much. So, I can get away without topping everyday. Also, I can't justify the cost of ATO systems for each tank. Space is a factor as well. I don't want to clutter the room with various containers.

[Sk8r]

There'd be no reason I can think of why a qt couldn't share a reservoir, on a different pump, granted no back-siphoning---BUT!---its a good idea to have a qt isolated from the DT in case of any spray or aerosoling of water that could carry infection or parasites from the qt to the dt. A curtain would work. A cardboard barrier.

[sbash]

Originally Posted by Sk8r

There'd be no reason I can think of why a qt couldn't share a reservoir, on a different pump, granted no back-siphoning---BUT!---its a good idea to have a qt isolated from the DT in case of any spray or aerosoling of water that could carry infection or parasites from the qt to the dt. A curtain would work. A cardboard barrier.

My ATO is gravity fed with a float valve (so it drips). I just moved so I am redesigning my sump area into a fish room. My QT will be 10 feet from the sump, and if I run a drip line on a float, there will be no splashing. I am going to take this into consideration, good idea!