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.