Neptune Systems OS-1 Optical Level Sensor V2

Optical sensors are the go to sensor if you want a reliable sensor over a long period. The Neptune Optical Sensor plugs directly into the FMM allowing you to monitor the level of your sump, mixing station, or any other reservoir with liquid in it.

This sensor plugs into your FMM and, using reflected infrared light, will signal your Apex when it changes state from being wet to dry or dry to wet. This sensor can be used for constructing your own ATO (auto-top-off), as a high-level warning sensor in your sump, water storage level sensor, and much more. The sensors can be mounted into custom brackets or through a hole in a vessel. Included are a fastening nut and silicone washer.

What’s Included?

1x OS-1 V2 Optical Sensor with nut and washer.

Warranty & Support

This product carries a 1-year manufacturer warranty on hardware from the date of purchase. Probes are consumable items and carry a 90-day warranty.

Warranty support is handled by us directly. Message our WhatsApp support with your order number and we will diagnose the fault first. Most cases are solved by replacing a single part, so you rarely need to send the whole unit. If the item does need to come back, it ships to our Delhi warehouse, and courier cost in both directions is borne by the customer. Your GST invoice is valid proof of purchase for the claim.

Backorder & Dispatch Timeline

This item is stocked to order. Back-orders are consolidated and placed with our overseas suppliers once a month, on the last day of the month, and all such orders are shipped before the 15th of the following month.

Back-orders cannot be cancelled once they have been placed with the supplier. If you cancel before that, payment-gateway charges of 2% plus GST are deducted and the balance refunded. In the rare case a supplier cannot fulfil the item, we will offer you an alternative first, and refund in full with no deduction if you would rather not take it.

Setup & Use

The OS-1 is a wet/dry sensor that reads reflected infrared light and plugs into an FMM. Use it for ATO control, high-water alerts or reservoir level checks. Mount it in a bracket, or through a vessel wall with the included nut and silicone washer. The cable is 10 ft long.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number, or email us if you would rather, and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 48 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.