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...
Skip to the end of the images gallery
main product photo
Skip to the beginning of the images gallery
Tunze

Osmolator 3 Auto Top Off w/ Tunze Towel

In stock
Out of stock
SKU
256510
Be the first to review this product
Discontinued by BRS Fresh
- +
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.

BRS Exclusive Deals

Exclusive Bundles

Top brands, deep discounts!

Learn More

BRS Exclusives

Bulk Reef Supply Exclusives

Shop high-value bundles from top aquarium brands to unlock deeper savings that you can only get right here at BRS. When it’s marked as a BRS Exclusive, you know you’re getting an extra value you won’t find anywhere else.

Shop All
Details

Next-Generation Auto Top Off System

  • Stable Aquarium Salinity Level
  • Plug and Play Convenience
  • Compact All-In-One Design
  • Built-In Safety Features
  • Tunze Towel Also Included!

 

Tunze has long been recognized for their auto top off systems and like its predecessors, the Osmolator 3 includes everything you need for installation (except ATO reservoir) with no software setup required. 

With its optical and thermal sensors, it ensures precise water level control and protection against overfilling-- all within a compact design. Designed for versatility, it can be placed in the sump's return section or on the aquarium's edge, depending on your setup.

 

The Optical Sensor

The large, precise optical sensor detects the water level with an accuracy of 0.5mm and is resistant to air bubbles, deposits, and scratches. The independent thermal safety sensor stops the ATO pump in the event of overfilling. The sensor's strong magnet mount is compatible with sumps/aquariums up to 15mm (0.59") thick. The protection cap helps prevent curious critters from reaching the sensor.

The ATO Pump

Each Osmolator 3 comes with a Turbelle High Jet pump to move water from your ATO reservoir to the aquarium or sump. This long-lasting pump has an impressive maximum head height, being able to pump just over 20 feet vertically. Run-dry and blockage protection is built-in.

 

 

Specifications

Max. Glass Thickness (Sensor): 15mm (0.59")

Max. Glass Thickness (Tube Holder): 22mm (0.87")

Max. Delivery Height: 6.2m (20.34')

Tubing Diameter: 6mm OD | 3.9mm ID

Tubing Length: 3m (9.84')

 

What's Included?

Osmolator 3 Sensor

Magnet Holder

Turbelle High Jet Pump

12V DC Power Supply

Tube and Tube Holder

Tunze Towel

More Information
More Information
SKU 256510
UPC 4025167493003
Aquarium Type Saltwater, Freshwater
Reviews 1
Write Your Own Review
You're reviewing:Osmolator 3 Auto Top Off w/ Tunze Towel
Your Rating
Product Questions

Product Questions

No questions yet. Be the first to ask the question!

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
Super Naturals Substrate - Zen Garden
CaribSea
Super Naturals Substrate - Zen Garden
From: $13.32

Choose Options
Iwagumi Substrate - Del Plato Sand (7.7lbs)
Aqua Natural
Iwagumi Substrate - Del Plato Sand (7.7lbs)
$15.73 $15.73

African Cichlid Mix - Original Substrate 20lbs
CaribSea
African Cichlid Mix - Original Substrate 20lbs
$15.70 $15.70

Midnight Pearl Bio-Substrate (5lbs)
Aqua Natural
Midnight Pearl Bio-Substrate (5lbs)
$12.99 $12.99

GloFish® Water Conditioner for Bettas
GloFish®
GloFish® Water Conditioner for Bettas
$4.33 $6.19

pH Test Kit
API
pH Test Kit
$7.98 $7.98

Bug Bites Color Enhancing Flakes
Fluval
Bug Bites Color Enhancing Flakes
$7.99 $7.99

African Cichlid Mix - White Sand 20lbs
CaribSea
African Cichlid Mix - White Sand 20lbs
$15.70 $15.70

Super Naturals Substrate - Jelly Beans
CaribSea
Super Naturals Substrate - Jelly Beans
From: $13.32

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

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