Innovative Marine's HydroFill ATO controller and pump system looks interesting on paper. Sensors made of chemically inert graphite suggest longevity in a salt environment. The unique air-lift pump is self-priming, will not back-siphon and can safely run dry. For someone with thousands in reef aquarium equipment, this will be attractive. So how did Innovative Marine follow through from paper to product? Well enough to offset cost of this premium ATO? Find out by reading the 3reef hands-on review of the HydroFill below. The first thing you learn about the HydroFill ATO system is that the pump and controller system are sold separately. This took some time for me to process, but I can see that there will be some may have an ATO currently that would like a sensor system that is less finicky. The sensors will be attractive to those with double float setups for example. Therefore they could be drawn to use the HydroFill controller and their existing pump. Rationalizing the $200 price could happen with prolonged use without issue. However, those that want the full HydroFill experience will have to pay an additional $100 for the air-lift pump. At a total of $300, this premium, higher that all other ATOs that I am aware of price, puts a lot of pressure on how well the controller and pump work together as well as integrate into your current aquarium setup. So lets start with the HydroFill pump. Air pumps are pretty sentimental to this guy. For those of you middle-age-holding-your-tummy-in types that have been doing this a while, you certainly can recall how big air pumps were with salt water aquariums back in the 1980's and '90s. We seemed to use them with everything back then. Today, not so much. Opening the box, I am immediately stuck by the size of the air pump. It's bigger than my Whisper 10 I currently have running in my refugium and it's more inline with the old Whisper 800 air pump with the big knob from back in the day. Some will have to make room in their stand or take advantage of the cabinet mount just to place it. Included are all the parts you need to hook the pump into your ATO controller system. These include, quick-clamps for all hose connections, 10 feet of silicone tubing, mounting brackets and return pipe. The instructions quickly remind you to take 2 measurements. The first between your return pipe and ATO pump and the 2nd between your ATO pump and reservoir. This is a time to measure twice and cut once or else you will be hoping around town looking for silicone tubing. You have been warned. The HydroFill pump can be mounted a number of ways: hang-on, cabinet mount or stand alone on rubber feet. For this review, I decided to go with the hang-on approach with the bracket and attach it to my sump. (My sump for this review is a 10 gallon tank I use to mix and hold new saltwater for my water changes) The HydroFill Pump Mounting Bracket Attaching the bracket to the pump was the first challenge as it required placing the first screw into the mount in mid-air and then screwing the screw in through a guide hole in the bracket. Once done, I was a bit stunned at the next realization. The mounting bracket is designed for rimless tanks or sumps. This decision was a bit odd to me. How many people have rimless sumps? As shown, the mount will go over the tank rim, but the pump will not rest flush against the side. And this issue carried over with the return pipe mount - it too was designed for rimless aquariums. For tanks with rims, Innovative Marine suggests to simply remove the mount and rest the return pipe on the rim. While it can do that, it is not flush nor very secure. This is a bit unnerving when you are pumping water through it. While safety was kept in mind elsewhere, it appears to have been overlooked here. For the review, I placed a thick credit card between the mount and the aquarium to help attach it to the rim. It was adequate for the review, but I would not be comfortable leaving it that way in real use. Innovate Marine may want to address these issues in future as rimless aquariums especially with rimless sumps are not as common and it is a frustrating first impression for a new user. Moving past these issues, I connected the hoses which was an easy affair with the supplied quick-clamps. It was time to connect the HydroFill ATO controller system. Noise Air pumps can be quiet loud and Innovate Marine's is very audible. I imagine there will be some that purchase the HydroFill ATO system completely unaware of the noise from the pump and then become quiet shocked when they turn it on for the first time. There are many great reasons why Innovate Marine choose this pump - it can run dry, does not require priming, very low (1w!) power consumption yet powerful and more… but the noise will be a negative. Bedroom tank hobbyists will struggle with it. Others with open setups or fish filter rooms will give it a pass and enjoy the benefits. That said, I was impressed with how fast HydroFill ATO pump drew water from my reservoir with 4 feet of head. This pump can pump 15 gallons an hour at up to 5 feet of head. An air-lift return is unique among ATOs and makes me wonder if there is a way to rig this system for live foods. Not sure how that would work but that could be fun. The HydroFill ATO Controller System The controller itself has a row of 6 LEDs that display the status of the sensors and pump. Strobing green lights from left to right indicate that both sensors are out of water and will activate the pump. Various other states will cause the LEDs to pulse or stay lighted. When both sensors detect water, the far right LED will remain on indicating a level statue and the pump will turn off. Unpacking the controller, one standout is the 3 prong plug receptacle for the top-off pump. The HydroFill controller can accept pumps up to 1000 watts. A nice touch that opens up options for use. Hobbyists tend to have a bevy of extra pumps around so a spare Aqua-Lifter or powerhead may be all that is needed. Oddly, the main plug of the controller is not grounded. An oversight that would prevent grounding and may be an issue for big pumps after all. The HydroFill Sensors Hardwired to the controller are two sensors that each contain two chemically inert graphite electrodes that extend from the sensor about 3/8" from the bottom. The electrodes will actually complete a low voltage circuit via the water in your sump or tank and switch a control relay. The sensors themselves are about 2 inches in length and shaped like oblique cylinders. A bit odd but the included magnet mounts make this a non-issue. These are nice magnet mounts that are strong yet easy to move. I was curious how sensitive the HydroFill is to water fluctuations, so I spent some time adjusting the sensors and placing them in and out of water. I soon learned that the low sensor must have the electrode probes about 1/8" below the waterline to successfully show a "low" status. If the water line dips slightly below this, the pump will be activated. Yet the high sensor probes merely have to touch the waterline to cause the control relay to switch and the "level" status to appear. Arranging the two sensors close together with one slightly higher than the other should keep your waterline stable with minimal variations. Yet the option is there to spread them apart to lessen the wear to your ATO pump or perhaps even have some fun with a tidal tank. This distinction separates the HydroFill from Tunze Osmolator which holds a tight line with its infra-red sensor. Which approach is better? Well I suppose that depends on your philosophy. Some will appreciate the options, while others will prefer a stable waterline over the life of the ATO pump. The strainer is a nice touch HydroFill Positives Durability Accuracy Self-priming pump Low power consumption HydroFill Negatives Noise of pump Price for complete system. Brackets only for rimless aquariums Impressions There is a lot to like about the HydroFill. The redundant electrodes & sensors and low power consumption should result in long life without failures. If I had large aquarium with thousands of dollars in equipment and livestock, I would give the HydroFill serious consideration. Especially if I had a filter room to hide that pump out of earshot. But others will pause at the price and footprint of the complete system - and wonder if its unique features are worth a bit more than the streamline Tunze Osmolator for example. It is hard not to make the comparison or notice quirks when you are paying over $200 for an ATO. Regardless, the premium ATO market is not crowded and Innovate Marine has put together a low power ATO that is accurate, built-to-last and easy to use. That alone should keep the HydroFill topping off tanks for some time. matt More: http://www.3reef.com/forums/3reef-radar/new-hydrofill-ato-innovative-marine-148516.html Innovate Marine Web site: http://www.innovative-marine.com/ FCC - This unit was sent to 3reef free of charge. We enjoyed out time with it and did our best to point out positives and negatives in the review. This unit will be given away in a 3reef contest.