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
Bulk Reef Supply

1/2 Gallon (3.5 lbs) Bulk GFO - High Capacity

In stock
Out of stock
SKU
000622
Be the first to review this product
$143.32 $143.32

- +
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.

Details

Why does BRS recommend this?

Phosphates are going to be one of the biggest battles we have with a reef aquarium.  The BRS GFO works even better in reactors due to it being denser than most other GFO.  The price is just about double of standard GFO however you only need to use half as much which equals out in the long run.  High Capacity is going to have less dust than almost all other GFO on the market and being able to buy it in bulk saves a ton of money.

High Capacity GFO is the best performing GFO we stock and capable of removing close to twice the phosphate as standard GFO by volume. We recommend this when you have a large tank or limited room in your media reactor.

Granular Ferric Oxide (GFO) removes phosphate from the aquarium and is one of the most commonly used filtration media used in the aquarium industry.  GFO is one of the few ways to easily maintain ultra low phosphate levels on a consistent basis. Maintaining these ultra low levels will help prevent algae outbreaks as well as treat existing algae issues. Your aquarium's glass will also stay clear and free of the green hue significantly longer. GFO is most commonly used in a media reactor like the BRS reactor or media bag.

Phosphate inhibits proper coral growth by incorporating itself into the corals skeletal structure which makes it difficult for the coral to grow by laying down additional calcium and carbonate (alkalinity) ions. Maintaining ultra low phosphate levels will increase the growth of any SPS or LPS coral.

Algae outbreaks are one of the most common reasons for a complete tank shut down. We recommend preventing them by maintaining an ultra-low nutrient level environment where it would be difficult for them to get out of control to begin with. It is much easier to prevent outbreaks than it is to treat existing outbreaks.

 

Two Types of GFO:

 

  • Granular GFO is varied in its shapes and requires the least amount of flow to tumble. Good for reactors.
  • High Capacity GFO is twice as dense as Granular GFO, so twice as much material will fit into a reactor. It's extremely hard and has less dust to begin with. Fewer fines will be created during use and transportation. By volume, High Capacity GFO will remove roughly twice the phosphate compared to the same volume of Granular GFO. Best overall performance.

 

Special note on fighting existing algae problems: Algae needs three main nutrients to grow: phosphate, nitrate and light. Reducing any one of these will significantly slow down algae growth but may not completely solve your issue. Once algae takes hold, it can be a difficult battle but it is winnable. The best offense against algae is to take preventative measures and attack nutrient before an outbreak is apparent. Use the following suggestions and be aggressive if an algae problem is already present:

 

  • Maintain undetectable phosphate levels with good feeding habits and use a phosphate remover like GFO. 99% of all phosphate is added to the tank via foods.
  • Control nitrate levels by reducing feedings, increasing the water change schedule and maintaining a properly sized protein skimmer.
  • Use nutrient free RO/DI water for water changes and top off water
  • Shorten your lighting period or intensity. In some cases aquarists have found replacing old bulbs that have fallen out of their intended spectrum helps as well.
  • Continuously remove as much algae as possible by hand.
  • Add predators - nothing helps an algae outbreak as much as critters who eat it all day long. Various tangs, lawn mower blennies, crabs and snails are all good options. It is also theorized that a healthy pod population will also control algae growth before it gets a chance to take root.



Note: All Bulk GFO is packaged by volume.

 

GFO Instructions

More Information
More Information
SKU 000622
UPC 853710007841
Aquarium Type Saltwater, Freshwater
Reviews 3
Write Your Own Review
You're reviewing:1/2 Gallon (3.5 lbs) Bulk GFO - High Capacity
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
Stainless Steel Straight Spring Scissors
Ultum Nature Systems
Stainless Steel Straight Spring Scissors
From: $30.79

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

Choose Options
BRS Fresh T-Shirt
Bulk Reef Supply
BRS Fresh T-Shirt
From: $22.99

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

Choose Options
Catappa Leaves 10ct
Liquid Gardens
Catappa Leaves 10ct
$10.49 $10.49

AquaStik Underwater Epoxy Putty - Stone Grey
Two Little Fishies
AquaStik Underwater Epoxy Putty - Stone Grey
 
0  Reviews
From: $12.83

Choose Options
Boutique Seiryu Stone
Ultum Nature Systems
Boutique Seiryu Stone
From: $35.79

Choose Options
Iwagumi Substrate - Garnet Sand (7.7lbs)
Aqua Natural
Iwagumi Substrate - Garnet Sand (7.7lbs)
$22.48 $22.48

Iwagumi Substrate - Colorado Sand (7.7lbs)
Aqua Natural
Iwagumi Substrate - Colorado Sand (7.7lbs)
$15.73 $15.73

AquaPlus Water Conditioner 8.4oz
Fluval
AquaPlus Water Conditioner 8.4oz
$6.79 $6.79

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
(Learn more)
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