The Eheim WaterRefill is a boxy looking Auto Top Off kit which could be forgiven for appearing like just another ATO, but it’s actually using a relatively new approach to sensing water level in aquariums. As far as we can tell, the Eheim WaterRefill is the only auto top off device which uses a single stage, external level sensor that only attaches to the outside of the tank, with no internal component or moving parts to foul or get stuck.
In recent years we’ve given Eheim some well deserved flack for releasing hokey products that fall short of the Eheim brand name but to our surprise, this time we’ve kind of got to give them credit for being first with an innovative product. With only a single external sensor, we presume that the Eheim WaterRefill might be using some kind of capacitive water sensor, which would be the first of its kind actually released as an ATO for the aquarium hobby.
We first observed a capacitive water level sensor at InterZoo 2018 in Germany last year at the Johnlen booth where they displayed this technology working precisely as an Auto Top Off device. Despite all the information and details on Eheim’s official page for the WaterRefill ATO there’s no illustration of the sensor’s business end and no details of how it works precisely, so the use of capacitive technology is only our best, educated guess. Nevertheless, replacing evaporated water from both fresh and saltwater aquariums is a very important function and one of the easiest to automate so Eheim certainly would have selected a technology that is reliable.
Our fascination with how Eheim’s WaterRefill works, the kit is actually quite complete with hoses, a pump, holders, connectors and electronics with a degree of smarts in that the main controller remembers how much water is required to refill the aquarium, but also has some adaptability with the seasons. The Eheim WaterRefill carries a sticker price of 139€ or about $156 which isn’t cheap, but isn’t out of line either considering it’s a complete kit with everything you need to create your own automatic top off solution, and the completely external water sensor is an added bonus. [Eheim]