The Tunze Osmolator 3155 is easily the most popular auto top off that we sell; it's purchased 5 times as often as any other ATO on our site! It's one of our favorites, too, because of it really sets itself apart from other ATO's with reliability, safety, mounting options and future flexibility. While pretty much any auto top off will be safe to use for a year or so, we want our tanks up for many years so reliability is one of our top concerns. A lot of ATO's rely on float switches for their primary level control, which in the long run fail pretty frequently since they rely on moving parts to function. The Osmolator uses an optical eye which a completely different technology to monitor the water level. This doesn't have any moving parts, and I've personally never seen this fail in the on position. In addition, the Osmolator has a safety float switch as a back-up sensor. Even if that somehow failed, it's equipped with a 10-minute internal timer to turn the ATO off completely if the pump is ever on for 10 or more minutes. Installation of is super easy and takes about 5 minutes. You'll need a container to act as your water reservoir, a food grade bucket works well. Find a convenient place to mount the control box using the included velcro strips. Take note of the three lines coming out of the control box, you have a power line for the included pump, a line to the optical sensor and a line for the float switch. The pump isn't connected directly to the control box by design, so you can route the cord through the top of your top off container before connecting to the control box. Note: Be sure to always place the water output above your auto top off storage container to prevent siphons. The final step is to connect your sensors to the included magnetic mount, with the optical eye pointing down and the float switch pointing up. If you don't have a sump, you can place the sensor mount directly in the tank. You can do the same in the sump at the level you'd like to keep your water at. Have questions? Let us know in the comments below! Be sure to hit subscribe so you don't miss our new video coming out next Friday. Connect with us on Facebook: Check out our pics on Instagram: *Legal Stuff* The purpose and content of this video is to provide general information regarding the products and their applications as presented in the video. Aquatic sales solutions, inc. And its officers, directors, employees and agents disclaim all express or implied warranties, in any way, related to the products and their application as presented in this video, make no representation or warranty regarding the products and the application as presented in this video and shall not be liable for any direct or indirect losses or damages of any type, including but not limited to punitive damages, or from personal injury or death resulting from or in any manner related to the video, and the products in and contents of the video. The viewer expressly agrees that aquatic sales solutions, inc. and its officers, directors, employees and agents shall not be liable for any damages or losses related to the products in and content of the video and hereby agrees to hold the foregoing harmless from any such losses or damages.