• Octo FW110 High Amperage Float Switch
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Reef Octopus

Octo FW110 High Amperage Float Switch

Octo FW110 High Amperage Float Switch

$99.99
$99.99
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Shipping calculated at checkout.

Aquarium Float Switch for ATO, Skimmer Protection, and Pump Shutoff

The Reef Octopus FW110 High Amperage Float Switch is a probe-style water level switch rated at 5 amps. It plugs directly into an outlet and controls whatever is plugged into its output cord, with no controller or additional hardware required. The FW110 handles up to 5 amps of combined load, which is enough to run multiple smaller pumps simultaneously from a single switch.

The switch works in two orientations. With the barrel float in its default position, the switch triggers on high water (shuts off or activates when the water level rises to the float). Remove the retaining ring, flip the barrel float upside down, and it triggers on low water instead, making it usable as an ATO activation switch for a top-off pump. This single mechanical adjustment covers the two most common float switch applications in an aquarium setup.

Key Features:

  • The 5-amp rating supports multiple pumps on one switch, with a combined load up to 5 amps.
  • Reversible barrel float switches between high-water and low-water trigger modes without any tools — remove the retaining ring and flip the float.
  • Includes a 6-foot grounded power cord for flexible placement in sump cabinets or equipment stands.
  • Probe-style design for precise, reliable water level detection.
  • No controller required; plugs directly into a standard outlet and operates standalone.
  • Usable for skimmer overflow protection, ATO top-off control, or pump dry-run prevention.

Ideal For:

  • Hobbyists who want a simple, no-controller float switch to cut power to a return pump or ATO pump at a specific water level.
  • Reef and saltwater setups using a protein skimmer collection cup or sump overflow application where a high-water shutoff is needed.
  • Anyone running a basic ATO system who wants a low-water float switch to activate a top-off pump without a dedicated ATO unit.

Pro Tips:

  • Use two switches for a belt-and-suspenders ATO setup. One FW110 set to low-water activates your top-off pump. A second set to high-water cuts it off as a backup. This gives you both trigger and safety shutoff without needing a dedicated ATO controller.
  • Keep the probe vertical and free from obstructions. The barrel float needs to move freely to trigger reliably. If the float gets fouled with salt creep or contacts the tank wall or equipment, it can fail to trigger. Clean the probe periodically and make sure it has clearance on all sides.
  • Check your pump's amperage draw before wiring multiple pumps. The 5-amp limit is the combined total. A typical small ATO pump draws well under 1 amp, but larger return pumps can draw 2-3 amps. Add up the nameplate amperage of everything you intend to plug in before connecting.

Online exclusive: this item is ordered in for you and is usually ready within a few business days. Choose in-store pickup, local delivery or shipping at checkout.

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