Fluval's Bio-Max Replacement cartridge for "U" Series underwater filters for U2, U3, and U4 filters. 

Size: 6 oz.

Free Shipping & Delivery:

Enjoy free shipping on any order with a sub-total over $75. Simply enter coupon code: FREE at checkout for Free Saver Shipping - (5-8 Business Days - not guaranteed). Only one coupon can be used per order. Free shipping excludes HI & AK.

Orders placed before 12:00 noon (PST) Monday - Friday usually ship the same day. Orders placed after 12:00 noon (PST) will ship the following business day. We only ship within the United States at this time!

FedEx has partnered with the USPS to offer our customers FedEx SmartPost to ensure on-time delivery at affordable shipping rates. Our Saver Shipping utilizes FedEx SmartPost for all packages under 9 lbs and are delivered in the last leg of transit via United States Postal Service. If you need your package faster on a guaranteed date we recommend upgrading your shipping service to FedEx Ground, Expedited or Overnight services. Business Days are Monday through Friday excluding all major holidays. Saturday and Sunday are not considered business days. The day your order ships is not considered a day in transit. A tracking number will be emailed to you for your convenience.

FedEx Tracking: www.fedex.com/tracking
FedEx Phone #: 1-800-463-3339

Low Price Guarantee:

Shop with confidence at Pet Mountain with our low price guarantee. Simply call us at 1-888-373-8686 with the competitor website and model number prior to placing your order and we will beat the price for you!

• Typographical errors will not be matched.
• Item must be new (not refurbished or reconditioned).
• At this time, price adjustments will be honored only for online stores.
• All price adjusting is at the discretion of Pet Mountain and is subject to change at any time.
• The price considered will be the total price of the item including Taxes and Shipping Charges, if applicable.

No Sales Tax:

Pay no sales tax if your order is shipping within the United States - (Excluding California). We are required by law to collect sales tax on orders shipped to California. Sales tax will be added to your order total and displayed on your order confirmation.

Customer satisfaction is very important to us, please read the following guidelines before submitting a return. If you need to cancel your order before it ships please call us at 1-888-373-8686 and reference your order number. Please have your order number ready when calling.

• Damaged / Defective Item(s) - Please call us at 1-888-373-8686 within 21 days if the item/s are damaged in transit. Please hold onto the item/s, original shipping box and packing materials. For defective items, please contact us within 60 days. For defective items after 60 days please contact the manufacturer directly to submit a warranty claim. Please do not refuse the package or attempt to return it yourself prior to contacting us. We will remedy the situation for you! Please have your order number ready when calling.
  
  
• Changed your Mind - You have 60 days to submit a return below. Items must be in their original condition including manufacturer packaging, manuals & components to warrant a refund minus the original shipping & handling charges. It is your responsibility to ship the item back to us. If you refuse the package all incurred shipping charges will be deducted from your refund. Refunds are issued within 1-5 business days after we receive your return.
  
  
• Product Exchanges - We do not do exchanges, simply submit a return below within 60 days and place a new order online. Items must be in their original condition including manufacturer packaging, manuals & components to warrant a refund minus the original shipping & handling charges. It is your responsibility to ship the item back to us. If you refuse the package all incurred shipping charges will be deducted from your refund. Refunds are issued within 1-5 business days after we receive your return.

Click here to submit a return.