aggie4231,
Thank you for your post. When placing your next order over the phone, you may redeem your credit by simply notifying the agent that you would like to apply it to your order. If you are placing the order on the Internet, please enter a comment in the "Notes For This Order" box stating that you have a credit on file that you would like applied to your order.
Nate M.
LiveAquaria
Drs. Foster & Smith