Skimmer Float Switch

How To Avoid a Skimming Disaster With a Float Switch

I am a big fan of preparing for the worst when it comes to keeping a reef tank and I constantly think about ways to prevent potential disasters before they happen. On several occasions in the past, my skimmer overflowed without warning and nearly dumped skimmate into my sump. I was lucky because I caught it early but it made me wonder how I could keep this from occurring in the future.

Some folks use waste collection containers connected to the skimmer cup to catch overflows but certain containers, when full, will not prevent waste from continuing to overflow onto the floor. However, other devices will shut a skimmer off when the container is full, although these automatic shut off containers can be pricey.

The DIY Route

I was on the hunt for a cheaper solution so I began to noodle around with some DIY ideas. The plan was to use my controller to shut the skimmer off when the switch was triggered. The lid on my skimmer has 4 large holes, which made me think it was possible to install a float switch vertically through one of the holes.

Ok, the wheels were turning! I ended up buying a standard float switch, a 5/16″ nylon screw (2-1/4″ long) and 3 nylon nuts. The float switch cost $10 and the screw and nuts cost $2. A $12 breakout board was also needed to hook the float switch up to my controller.

The top part of the float switch was threaded so my plan was to utilize those threads to attach it to the nylon screw with one of the nuts. Now, the challenge was to find a hollow nylon screw to thread the wires of the float switch through it and out the top of the skimmer. Of course I could not find one anywhere but the guy at my local hardware store was able to drill a hole through the screw with a 1/8\” drill bit. Let me tell you, it was not easy! Using a drill press would have been much less painful.

float switch skimmer cup

Below are two videos explaining how to connect the float switch to either a Neptune Systems APEX controller or a GHL Profilux 4 Controller.



Whether it is this gizmo or something else, it does pay to be proactive about preventing potential disasters. As the saying goes, an ounce of prevention is worth a pound of cure!

Additional Resources

If you would like some help with a new tank build, including help designing a custom aquarium, or help re-configuring your current setup then you can visit this page for more information. And if you are looking to add some equipment, I do sell GHL, Pax Bellum, Reef Octopus Calcium and Kalk Reactors and Royal Exclusiv products, including Dreamboxes, which is the equipment I use and recommend. I also sell Reef Brite metal halide and LED fixtures as well as Maxspect & IceCap Gyres.

As for additional insights and information, please explore my many other reef tank and SPS related articles as well as my YouTube channel. For an even deeper dive into reef tank care you can check out my Reef Keeping Master Class. This online course is an immersive and one of a kind educational tool designed to help reef aquarium hobbyists build and maintain a beautiful SPS reef tank. The course is a series of video presentations with some supplemental video from my YouTube channel. There are also quizzes to help students retain and understand the information presented in the course.

Need some frags…..I can help with that as well 🙂 Please visit my SPS Frag store to see what is available.

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