Who is this for: Anyone that uses a sump/refuge and does not have a controller! What it does: Adds a layer of protection to prevent your display tank from overflowing in the event your overflow stops working, your overflow box looses siphon or flow slows down and can no longer drain quickly enough. What exactly it is: This is a kill switch that will cut power to a device (ie your return pump) when a float switch is triggered and keep the power off until you fix the problem and press the reset switch. When I originally setup my tank I was: A) Extremely concerned about my display tank overflowing and that water making quick work of my lovely pine wood floors underneath it, and B) On a budget, like most I’m sure. I searched and searched for solutions and didn’t find much, other than expensive controllers. I found one or two threads from someone inquiring about this but never saw any follow-up or a definitive how-to. Most suggestions simply pointed to rigging an ATO system. Somewhere along the line I found a link to Aquahub Homepage. They offer a few different DIY kits and I decided to pull-the-trigger. I went with theTop-it-Off Kit Deluxe so I’d have a few extra parts in case I ever wanted to expand or if I broke something. I especially liked theirMold-a-Holder and the Slosh & Snail Guard to help prevent the float from prematurely being activated from water sloshing around or a snail jamming it up. I received my kit very quickly and assembled the kit using the included instructions. The kit worked as it was designed, but now how I intended it to be used. I positioned the float switch just above my normal water line of the display tank and found that when the water level rose enough to set off the switch, it would kill the pump as I had intended. BUT as we all know, when the power is cut to the return pump, water will quickly be sucked back down to the sump and immediately lower the display tank. Well this would in turn lower the float switch, allowing the pump to turn back on. In my small 46gal bow, this cycle took about 5-8 seconds. My biggest concern was if this overflow event happened while I was at work, it could potentially cycle hundreds of times before I got home to fix the problem. This cycling could lead to premature failing of the relay and the pump staying on anyways, in addition to excessive wear and tear on the pump and other equipment. I needed something that would only turn the pump off and not back on until I could come home and fix whatever the problem was. After about a dozen emails back and forth to Patrick at Aquahub, we finally found a solution to wire up the relay correctly to allow my desired functionality. This specific wiring is very much different than what comes in the included instructions. I’d like to thank him a TON for spending the time that he did to solve this problem. The only extra item I needed was a toggle switch that I purchased at Radio Shack. I could have purchased it right from Toggle Switch Aquahub if I had originally known I would need it. So, without further ado, here is the schematic to PROPPERLY wire up your Aquahub kit to prevent your display tank from flooding if your overflow/siphon failed for whatever reason. I’m not going to document all of the other parts of the install (like the mold-a-holder, snail & slosh guard, extension cord modification, etc) because it’s all covered in the install manual from Aquahub. Other than reversing the float, the attached schematic is the only thing you’ll need to do differently to perform how this thread is intending. The schematic is also assuming that you're using the Relay Socket included with the kits, but you can use the referenced numbers to figure out where to wire it directly up to the relay if you so desire. Once you have it hooked up, plug everything in and test. The float should turn the system off until you toggle the switch off and the on again. Make sure you took the clip off the bottom of the float and reversed the float itself. Also make sure that you don't leave the switch in the wrong position. If you do then it completely disables the float and your pump will continue to run. Take a second to label your switch "Armed" and "Reset," or whatever you see fit. p.s. I have no affiliation with Aquahub. I was just so impressed with their customer support that I felt the need to spread the word about em. For all I know one could use any other brand's ATO kit. Not sure if the above relay and/or relay socket wiring diagram will apply though.