This is a great product for the price. I use it on my 40 breeder QT tank and have had no problems.

I can't believe, I went so long with out one...lol

For the money it is an ok ATO however the floats tend to stick and will mess with your salinity. I had to put both floats in the sump as a safe guard so that if one float fails the other will turn off the ATO. I have had multiple instances were it has nearly overflowed my sump.

The JBJ A.T.O. system is a good, simple auto top system. I have been using it with absolutely no problems. My only complaint is I wish there were more mounting options included with the sensors. I think if you are using a traditional system, you would have no problem. My water storage is a little unique, so I had to modify the sensor bracket.

I love JBJ product. This ATO is well designed and easy to set up. I will order another to use from my freshwater tank.

What this unit really needs is a way to double up on the fill sensors. That way if a snail gives one a ride it would not cause the tank to overfill and ruin your salinity. In other words, the unit would have to recognize when both sensors are calling for top off water to come on.

well constructed, and love the ability to use in many different ways.. I can't believe, I went so long with out one...lol

The JBJ ATO is a very simple design. It has a nice looking control module that nicely mounts to the inside of my tank stand, hidden but still up off anything that might get wet. The only drawback I had was that there was no good way to mount one of the sensors in my RODI reservoir so it kind of just floats around in it.

This is a great ATO switch. The only thing that I don't like is that the ATO checks every ten seconds to see if it is full and then turns off. So on a smaller tank that not turning off for possibly 10 seconds might cause salinity swings.

I installed the JBJ ATO over the weekend, it doesnt come with a pump so I purchased a Toms Aqua lifter pump from my local fish store. The unit works perfectly, I check my water level every morning and the level is always at the line I drew on the side of my sump.

pretty simple idea and thus simple enough to instal. The only complaint I have with this is there arent any instructions in the manual describing the level at which the floats are activated. took me a few minutes to find the "sweet spot".

Other than that this has been a worthy purchase. keeping my SG steady as opposed to dumping a gallon of water everyday is the first step in keeping a healthy reef. Many thanks to JBJ

I like this unit a lot. Makes it easy to use and also a must if you have a sump.

I have had this on one of my tanks with a Toms aqualifter for about 1 year now. Has always worked flawlessly, the aqualifter is a perfect pump for it as its quite,doesnt back siphon, there is no danger of burning it up either. the JBJ controller is easily adjusted for sump level and pump maximum run time.I Would recommend this for anyone looking for a reliable auto top off system

Way cheaper than competition but does not show in its quality. Works great so far and does what it needs to do..top off.

Low cost is nice, but in this case you get what you pay for, & I'd rather pay a little more for an important function.

Went on vacation for a week, thank God I had a tank sitter - he found the sump water level dangerously low 3 days into my vacation, with the return pump spouting tons of bubbles into the display tank. Good thing the return pump didn't run dry - would've fried it. Could've gone the opposite way, with the ATO pump running until it overflowed the sump!

Randomly it'll quit working - pump light is on but pump not engaged, confirmed the pump is fully functional. ATO box has to be powered off & back on, usually it'll reset back to normal the first time it's power-cycled.

This is an update to my review below. Initially was having problems with it automatically timing out randomly when it would turn the aqualifter on. Was leaving for vaction for three weeks and had no time to get a replacement. Worked around it by having the reefkeeper turn it off an reset it every 45 minutes. I've been monitoring it by cam while I'm on vacation. 10 days in, I wake up this morning and log in and one of my water alarms is going off. It has failed now in the on position. Every 45 minutes when the reefkeeper rests it, it's kicking on for the max of 14 before it times out. Can't tell if my floor is flooded yet and had to make an emergency call to a friend that's been checking on the tank to head over and unplug the damn thing. Total junk, thanks JBJ. If you are using this, I highly recommend you don't rely on it to go on vacation.

Easy setup and works great with 1/2 hose and MJ1200. Dont forget to get a pump when buying this. After research I decided not to go with the aqualifter pump due to head pressure and friction loss in tiny tubing.. Get a better pump and this unit and your set.

Another great JBJ product, couldn't be easier than this. Works great, a must have for anyone using a sump.

This ATO does exactly what you expect it to do. JBJ gives you a few options on how you would set it up, and although I am not an expert I think they include every applicable way to work an ATO.

I have one sensor in the third chamber of my sump and the other in a bucket full of fresh RO/DI water. When the water level in the sump gets low, it fills it. If the sensor in the bucket gets triggered it stops pumping water, which saves the pump.

I paired this with a Marineland Maxi-jet 400.

I just got the JBJ ATO and it's doing the same thing others have reported on various forums. Randomly, sometimes as much as once an hour, the controller turns on but with in a few seconds goes into time out mode shutting the pump off. I have it set to the max, which lets it run for about 13 1/2 minutes when it's working the way it's suppose to. Some have said the aqualifter may not be drawing enough power, like the reefkeeper problem with Koralia pumps on the solid state relays. I plugged a lamp in, in addition to the aqualifter with no change. So I'm not blaming the aqualifter at this point. Power draw doesn't seem to be the problem. I believe it's a problem with the electronics of the ATO itself. I found a work around on the internet of putting a timer on the ATO using my reefkeeper. Once an hour the reefkeeper turns the ATO off and back on resetting it. This works fine, but my confidence in the ATO isn't that great since I have to manipulate it to work. If the timeout becomes frequent enough, eventually it won't keep up, and worried it will end up having some other failure. Wishing I would have went with the Tunze now, which I'll probably do, and end up almost $300 into an ATO vs $200 if I had bought the Tunze from the beginning. I love BRS, but looking at the return policy for the first time, it states warranty issues must go through the manufacturer, vs. being able to return a defective product directly to BRS. I'd like to swap it for a Tunze, rather than trying to get it fixed or replaced. So that was a disappointment also. Buy yourself a different ATO.

Don't be fooled by two float switches - they don't work as you'd expect. Instead of redundancy - 1 "high" switch as a backup in case the "low" switch fails or is blocked - it's just 1 switch for minimum water level and 1 switch for maximum water level (Mode B). Or 1 switch in the ATO reservoir to protect the pump from running dry (Mode A). Anyone serious about safe ATO wants redundant switches in the sump/tank. Now I have to decide if I want the Tunze or DIY with my controller.
More minor concerns are the mounting brackets for the float switches. They don't fit over the rim of my tank very well and the height setting is adjustable in only large increments.
The float switch "guards" don't look like they'd keep anything out - any small to medium size snail could get in there and block the float's motion.
All together a disaster waiting to happen.

I've ordered two now, one about a year ago for my main tank and now this for my pico. ATO units don't need to be complicated. They just need to do three things:

-Transfer water from a reservoir to your sump/tank.

-Not overflow your sump/tank.

-Shutoff when reservoir is empty to prevent pump failure.

This product does all three, but does not come with a pump so I'd recommend the aqualifter.

Feels a little cheap but runs like a champ. I've had one for over a year with no hiccups and just ordered another one for a frag tank.

I really regret this buy.....got it for a friend tank....My 2 Tank are on an Osmolator....never had issue....But the JBJ failed to restart after a power outage....no more light nothing !