Bulk Reef Supply

Float Switch - Horizontal Mount

In stock

- +

Recommended for water applications like level controllers, auto top systems or other aquarium uses

  • Normally closed or normally open (see more)
  • 14” leads (22 gauge wire)
  • M16 straight threading - includes nut and silicon o-ring
  • 5/8" Mounting hole required


Mounts with wires outside of chamber.


Horizontal Mount Float Switches are great for:

  • General water level control applications
  • Aquarium top-off applications
  • Humidification/de-humidification applications
  • Hydroponics project
  • Water features
  • Air conditioning drain pan applications


Don’t use in heavy duty applications like sewage pumps.


Great for water. Check your fluid's specific gravity.


The wires complete a circuit when the float is down. You can reverse the operation by removing the clip, turning the float upside down and replacing the clip.


A pump rated at just 5 watts can destroy a float switch rated for 50 watts, locking it in the “on” position and pumping a lot of water where you do not want it.


The magnetic reeds enclosed in liquid level sensors are extremely reliable and long-lasting when utilized properly. Failures are nearly always a result of current overloading. Pumps, solenoids and many other devices that require control by a liquid level sensor carry "steady state" current ratings. These devices can draw ten times (or more) their steady state power ratings on start-up or shut-down. When the reeds inside our switches are exposed to this kind of "spiking voltage" they can overheat and become deformed. In some cases they may even weld together or break off, causing the switch circuit to remain closed (or open) regardless of the level of the float. Deformed reeds can also function intermittently, causing problems with troubleshooting. A 50-watt float switch can be destroyed by a pump rated at 6 watts and, unfortunately, it may take many cycles before the failure occurs.


Because they can destroy an otherwise very reliable float switch, care must be taken to completely isolate the switch from the current drawn by pumps, solenoids or other devices subject to spiking voltage. Resistors or diodes may be used, but the most common solution is to utilize a circuit board or a relay.


In the illustration, a relay acts as a switch for a pump, thereby isolating the float switch from any spikes that the pump may draw. The float switch turns the relay coil on and off. In this way, the only current handled by the float switch is that small amount required by the relay coil. Please consult with your relay supplier to assure that the relay current requirements are well within the specs of the float switch.

More Information
UPC 793420067103
Write Your Own Review
You're reviewing:Float Switch - Horizontal Mount
Your Rating
Only registered users can write reviews. Please or

Product Questions

Can this be wired to use with an Apex Pro controller?
Question by: Greg on May 3, 2023, 12:08 AM
Yes, you'll just need the Neptune Breakout box to wire this float switch to the apex.
Answer by: Chad (BRS Staff) on Jun 6, 2023, 4:52 PM
Will this work upside down? I need to cut power if the reservoir is empty.
Question by: Ron on Feb 20, 2022, 4:31 PM
Hey Ron, thanks for the question! This is a possible application for this, yes!
Answer by: James Johnson (BRS Staff) on Mar 3, 2022, 3:18 PM
Will this work with a tunze nano
Question by: Joe Cerillo on Dec 27, 2021, 11:19 AM
Hello Joe, Thank you for the question.

Tunze does not recommend using other float switches, if you need a replacement Tunze Float Switch you can order those directly from Tunze https://www.tunze.com/US/en/details/3152.300-sensor-for-3152.html. They have a US distributor that will ship directly from the US. I hope that this was helpful, but, please do not hesitate to contact us again if you have any further questions.
Answer by: Christian (BRS Staff) on Jan 7, 2022, 10:55 AM
If used with Neptune apex BOB, do I need the relay that you talk about in the product description ?? Thanks!
Question by: Bill on Feb 7, 2017, 10:07 AM
Great question! When using a Breakout Box, there is no need for any additional relay. You simply connect one wire to a numbered switch outlet and the other to the GND. :-)
Answer by: Randy on Feb 7, 2017, 11:24 AM
Can this be connected to vertex cerebra?
Question by: Awais Sheikh on Dec 28, 2016, 3:20 AM
Great question! This float switch will not work with the Vertex Cerebra. In its current form, the Cerebra does not have connections for the bare wires of a float switch. You would need the Vertex float switches with 6-pin connections. :-)
Answer by: Randy on Jan 2, 2017, 7:55 AM
What size drill bit is needed for this?
Question by: Robert on Jul 2, 2016, 7:17 PM
Do you sell a 120v relay 3 prong plug that can be utilized with this device to turn a pump on or off?
Question by: David on Aug 27, 2014, 11:17 AM
Hi David,

We do have a relay but it is part of an ATO kit that includes a standard vertical float switch. You can use the horizontal switch in place of the included switch.

I hope this helps!
Have a great day :)
Answer by: Bulk Reef Supply on Aug 27, 2014, 11:17 AM
Is this switch compatible with the neptune apex breakout box for use with things like water level monitoring?
Question by: Jeremy on Apr 30, 2014, 7:13 PM
Hey Jeremy,
You could certainly use these with the Neptune breakout box.
Answer by: Bulk Reef Supply on Apr 30, 2014, 7:13 PM