The store will not work correctly in the case when cookies are disabled.
Bulk Reef Supply Saltwater Logo
Bulk Reef Supply Freshwater Logo

FREE SHIPPING: Dry Goods Orders $49+ & Live Animal Orders $179+

Skip to Content
Menu BRS Freshwater
My Cart
    • My Account
    • My Wish List
    • My Orders
    • Address Book
    • Sign Out
    • Reward Points
  • Sign In
Bulk Reef Supply Mobile Menu
Close

Quick Links

  • DEALS
  • Gift Cards
  • What's New
  • Education
  • Clearance
  • Open Box
  • PR Rewards
  • Shop Brands
  • FAQs
  • Saltwater
Menu
Weekly Deals Weekly Deals
Sign up to be a Reward Member Earn Reward Points
Returns 365-Day Returns
Experts Aquarium Experts
  • Weekly Deals Weekly Deals
  • Sign up to be a Reward Member Earn Reward Points
  • Returns Risk-Free 365 Day Returns
  • Experts Aquarium Experts
Loading...
Neptune Systems

MOS Magnetic Optical Sensor

In stock
Out of stock
SKU
251253
Rating:
75% of 100
2  Reviews Add Your Review
$59.99 $59.99

- +
Add to Wish List
Risk Free 365 Returns

Your Satisfaction Guaranteed With
365 Day Risk Free Returns

No longer need what you ordered? Ordered one too many? We've got your back.


Return new, unopened products in original packaging within 365 days for a full refund.

Under 60 days? No problem. We’ll issue your refund to the original form of payment. Over 60 days? Still no problem. We'll issue your refund in the form of store credit, which you can use like cash on our website.


Return unused, open box products within 30 days.

Open box but still unused? We can help. We’ll issue your refund to the original form of payment minus a small 10% restocking and handling fee.

Some exclusions apply, for more information go to Return & Replacement Details.

Skip to the end of the images gallery
main product photo
Skip to the beginning of the images gallery
Details

Modern & compact magnetic water level monitoring

  • Improved look, feel, and design 
  • Precise water level control
  • Built-in magnetic mount
  • Silicone-encased external magnet
  • Completely waterproof
  • Compact form factor fits into tight spaces
  • Strong magnetic mount suitable for glass or acrylic up to 1/2" thick

 

The Neptune MOS replaces the previous OS-1 Optical Sensor and features an updated design that fits into tighter spaces and helps to prevent water incursion into the sensor. The MOS plugs into an Apex FMM port and uses reflected infrared light to 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 on any type of reservoir that has up to 1/4" thick walls.

More Information
More Information
SKU 251253
UPC 653078004991
Aquarium Type Saltwater, Freshwater
Reviews 10
Write Your Own Review
You're reviewing:MOS Magnetic Optical Sensor
Your Rating
Product Questions

Product Questions

Is there an extension cord available for the Neptune MOS? I would need to run the cable another 10 feet to a remote saltwater bin.

Thank you.
Question by: Christopher Hill on Mar 10, 2023, 2:29 PM
Thanks for the question! At this time there are no Neptune authorized extension cables. for this application, we'd recommend installing the FMM closer to the bin and doing an AquaBus extension instead.
Answer by: Kyle Thomas (BRS Staff) on Apr 27, 2023, 3:37 PM
How long is thew cable?
Question by: Benoit Martin on Feb 12, 2023, 2:21 PM
this cable will be 5 meters.
Answer by: William Reed (BRS Staff) on Mar 16, 2023, 10:13 AM

SIGN UP TO JOIN THE COMMUNITY & STAY CONNECTED

Our email newsletter is your front-row seat to the best deals, educational videos, new products and more.

Sign Up Now
BRS Fresh https://media2.cdn.bulkreefsupply.com/media/logo/stores/1/BRS-Logo-498x174.png https://fresh.bulkreefsupply.com/
BRS Fresh Bulk Reef Supply
  • Facebook Opens a new window
  • Youtube Opens a new window
  • Instagram Opens a new window
  • TikTok Opens a new window

Contact

  • 763-432-9691

  • 8am - 6pm CT M-Th
    9am - 4pm CT Friday
  • support@bulkreefsupply.com
  • 6325 Sandburg Road, Suite 200
    Golden Valley, MN 55427 US

About Us
About Bulk Reef Supply
Careers
Mr. Chili Sustainability Alliance
Affiliate Program
Terms & Conditions
Customer Center
Contact Us
Preferred Reefer Program
Returns & Replacements
Payment, Pricing & Promos
Shipping & Delivery
Wholesale Customers
APL Star Logo
© 2026 Aperture Pet & Life. All Rights Reserved.
Privacy Policy

item(s) Added to Your Cart

Product Name

View Cart Checkout Now
You may also like
Iwagumi Substrate - Del Plato Sand (7.7lbs)
Aqua Natural
Iwagumi Substrate - Del Plato Sand (7.7lbs)
$22.48 $22.48

Red River Slate
Ultum Nature Systems
Red River Slate
From: $14.00

Choose Options
BRS Fresh Hat
Bulk Reef Supply
BRS Fresh Hat
$24.99 $24.99

Pest Snail Catcher & Remover
AquaZen
Pest Snail Catcher & Remover
$20.00 $20.00

AI Freshwater Sticker
AquaIllumination
AI Freshwater Sticker
$2.99 $2.99

Malaysian Driftwood
Ultum Nature Systems
Malaysian Driftwood
Rating:
100%
1 Review
From: $7.99

Choose Options
Flamingo Bio-Substrate (5lbs)
Aqua Natural
Flamingo Bio-Substrate (5lbs)
$12.99 $12.99

River Rock/Sea of Green Aquarium Backgrounds
SeaView
River Rock/Sea of Green Aquarium Backgrounds
From: $3.50

Choose Options
Betta World - Diamond Black Substrate (1lb)
Aqua Natural
Betta World - Diamond Black Substrate (1lb)
$7.48 $7.48

Super Naturals Substrate - Gemstone Creek
CaribSea
Super Naturals Substrate - Gemstone Creek
Rating:
100%
1 Review
From: $13.32

Choose Options

Login and Registration Form

  • Login
  • Register

Registered Customers
If you have an account, sign in with your email address.
Forgot Your Password?
or

Login with Your Social Profile Login with

Personal Information
Sign-in Information
Password Strength: No Password
Back
or

Login with Your Social Profile Login with
  • Forgot Your Password?

Please enter your email address below to receive a password reset link.
Go back