HydorSmart Level Controller, Automatic Top Off, ATO

First, this product requires the appropriate lifter pump rate for it, I 100% suggest you not shop around and just get the Tom's Aqua Lifter Pump rated at 3.5 gph, which typically sells for around $15 on Amazon. It mates perfectly with this ATO. You will probably not find a cheaper pump that is dependable and matches the gph this ATO needs.Second, the directions that come with this product are horrible. The video provided is moderately helpful, but it makes an assumption that individuals using this ATO are topping off their display tank, or that they have a raised sump. This would negate most siphoning issues most of the reviewers are happening because the setup would inherently have zero siphoning issues. Many of us using this ATO are using it to topoff a sump tank that feeds the display tank and not directly into the display itself. Because of this, most of our sumps are in fact floor level or close to it and therefore you run into issues with gravity fed siphoning. In addition to getting the right pump, you have to understand the correct principles of a siphon. In this case, you DON'T want a continuous siphon to happen, which is the reason for the lifter pump. For those that have used mechanical ATO's with gravity fed topoff tanks, this is literally the opposite principal. First, you want your siphon tube from the water topoff container to be the lowest point in your topoff system. This includes the highest point in this tubing, not just the opening. So if your reservoir tube goes up, which for most of our bucket style toppoff reservoir containers, the tube goes up and out of a drilled opening, this top most part must then be lower than the topoff fill tube side. I am using a New Wave Enviro BPA free 5 gallon water jug for my reservoir and initially, I had the tube coming out of the top cap, which is very high up. In my sump which is a 20 gallon long, this was far too high because it was higher than any point in my sump. To fix this problem, I drilled a hole lower in the jug that was lower than the topoff side. Second, you want the Tom's Aqua Lifter pump to also be higher than your topoff reservoir. This is because there isn't a shut valve in it, so if a gravity fed siphon is started, there is nothing that stops it once it starts even if it is no longer receiving power from the Hydor ATO. The directions try to tell you in a generic picture about this, but doesn't give any descriptions.So to keep it simple, raise your topoff side to include pump higher than your reservoir side tubing. This might be tough for many of us that have your sump at the same level as your topoff reservoir. I had to raise my Aqua Lifter pump using a plant stand to get it higher than the tubing coming from the water jug. This way, once the Hydor ATO senses the max level has been reached, it will shut power to the Tom's Aqua Lifter. Then, the pump is too high to maintain gravity fed siphoning. Also, keep in mind that the fill tube must also be higher than the topmost part of your reservoir feed tube. This wasn't too hard for me because I have the fill tube hanging over the top edge of the sump tank. You don't want the top off tube to be in the sump water. If you have a lower reservoir tank and a taller sump tank, this will probably be an easy setup. Tom's even sells a hanger for the Aqua Lifter pump that lets you hang it on the side of your tank near the top. But for those of us running shorter sump tanks (mine is roughly 14 inches tall), it will take some planning. Another solution, if possible, would be to raise the level of your sump tank. However, my tank was already established and plumbed accordingly, so it would have been a pain to raise it.Once I figured out the correct siphoning, this thing has been a lifesaver. Thanks to all those previous to me that recommended the Tom's Aqua Lifter pump. I love the magnet style sensor attachment, as it works just like my powerhead. I think it is literally the same magnet system as their Hydor Koralia powerhead, so much more reliable than a suction cup. I find that once the temperature based sensor registers that the water level is below the min level sensor, it turns the ATO pump on in about 15 seconds. The Tom's pump trickles the water in my setup, it fills the return chamber of my sump back to max level in a few minutes, not too quick and not too slow. Once registered, it turns off in 15 seconds (approximately). Unless you have a bad siphoning design, this seems to be working flawlessly and I haven't had issues with overfilling. If anything, it keeps the salinity level in a very close range due to such a small fluctuation causing it to fill (if using it to top off a return side in your sump). This is great in keeping stability in your saltwater setup.One thing I don't like is how it doesn't seem to have a secondary backup sensor, so hopefully this electrical type sensor is reliable, I will update with time if it starts to malfunction. So far, it has been running for about a month. I do like how it doesn't rely solely on a mechanical float sensor that can gunk up with salt and get stuck. Also, it takes next to no room in my sump return tank, unlike mechanical sensors and/or float valves. If you are limited on space for your ATO sensor, this is a good choice.In all, highly recommend this ATO. All pieces seem to be of high quality and a very nice and clean design.Update 7/27/18: Now going a few years strong with zero issues. Love this thing!Update 3/16/20: Several years of continuous use, zero issues. I'd have to check the receipt, but I'm guessing I'm at least five years in.

I bought this auto top off in July 2016. It's still running strong and doing great over a year later. Every once in a while, you need to clean off any calcium deposits on it, But that goes for any other auto top off as well for it to function properly. The alarm on it can be a little tricky, if I'm changing the water in the tank and the water level in sump rises, It will set the alarm off (as it should). But, once I restabilize the water level, about the half the time the alarm shuts off on its own, the other half I have to unplug it and plug it back in for it to stop beeping. Not a huge problem overall but sometimes I wish it would always reset itself. Other than that, I love it.When I bought it last year, the price was only $70 and now it's about 100. I'm not sure why the price increase? Maybe The company has established that it's a pretty good auto top off and can sell it for a higher price?Also, I have experience with the Smart brand auto top off. Ive had problems with that particular auto top off pump going bad. Between the two I would definitely pick the Hydor with the toms aqua lifter pump.One more thing, others have commented that the water drops too low before the top off kicks in. My sump has a designated return pump area where the auto top off is, so the water rises and falls much sooner than if I had the auto top off set up in the main display large tank. This would likely happen with any auto top off and I don't feel this is an issue with the actual Hydor auto top off but instead an issue with how others have set it up on their main display tank.UPDATE 11/27/17- I woke up this morning to the hydor beeping. This happens sometimes if I forget the fill the ATO water container and it runs out, but this time the reservoir was full. I found the problem was that the Toms aqualifter pump had a piece of trash stuck in the tubing and it was only pumping a trickle of water. The Hydor ATO has a safety feature so that after the hydor ATO turns on the pump for more than about 7-8 min without the water reaching the top sensor, then the ATO stops the pump and it starts beeping.I cleared out the piece of trash in the tube and the pump worked normal and the whole ATO worked well. So again I am happy with this ATO and it is still going strong.Moral of this update is that if your pump is not strong enough to pump all the water needed to reach the cut off sensor in about 5-8 minutes, then the beeping will continue. I suggest you have a sump with a designated return pump section where the ATO goes so the pumped in water will fill within the time frame, but also not a pump so strong that fills so quickly that the pump reaches the top sensor too fast and sets off the overfill alarm. The pump has got to be just right.Update 7-23-19After owning this auto top off for three years now, it still works perfectly. I have a modified bean animal type drain from my reef tank into my sump which keeps the water level very stable in the sump other than evaporation. Still using the toms aqua lifter pump and I’m on my second one still going strong. I’m considering upgrading my reef tank from a 180g to possibly a 300 gallon in the next year and I will probably keep using the hydor as my auto top off. If it ever does fail I will try to get back on here and update the reviewUpdate 4/16/20I decided to get out of the hobby. Too busy with work and kids. This ATO worked well for me the nearly 4 years I was in the hobby of salt water tanks. I have cleaned it up and will be selling it to someone in my reef club in an hour. Sad to see it go but it worked well for me.