Great Aquariums Start Here
Live Chat Support
    Free Shipping On $75+
  • FREE Shipping On $75+
  • 14-Day Low Price Guarantee
  • Low Price Guarantee
  • Same Day Shipping
  • Same Day Shipping
FREE Shipping on
Orders Over $75
Standard ground shipping (1-7 business days) starts at a low $4.99 and most orders over $75 ship FREE. Learn More
If you find a product we sell for a lower price at another online store, we will match their price to ensure you always pay the lowest amount when you shop with us. Learn More
Same Day Shipping
We promise to ship your order as fast as humanly possible. In fact, 99% of orders placed before 2 pm EST ship the same day! Learn More
RO/DI Systems
Questions? Contact Us
Here's the deal
When you buy a reverse osmosis (RO) or reverse osmosis deionization (RO/DI) system from, you’ll receive 15% off all your replacement sediment filters, carbon filters, DI cartridges and membranes FOR LIFE.

So how does it work? Simple!

Just purchase any RO or RO/DI unit you desire from our online store. Any order you place thereafter that includes a replacement sediment filter, carbon filter, DI cartridge or membrane will automatically have your 15% discount applied when we process your order. You don’t have to do a thing!

Shop RO/DI Systems & Accessories

Aquarium reverse osmosis systems remove impurities from tap water to ensure your aquarium is free from heavy metals, pesticides, phosphates, chlorine and chloramines. Aquarium reverse osmosis systems are commonly abbreviated as RO systems; reverse osmosis/deionization units are generally referred to as RO/DI units. Aquarium reverse osmosis filters are available in economy 2-stage units and top-of-the-line 4-stage units. While an aquarium reverse osmosis unit is useful for all saltwater aquariums, RO/DI units are recommended for saltwater reef aquariums. By utilizing’s “15% off for Life” promotion, you’ll receive 15% off all your aquarium reverse osmosis water sediment filters, carbon filters, DI cartridges and reverse osmosis filtration membranes when you purchase an RO or RO/DI unit from our store.

This item is temporarily unavailable but will be back in stock soon.

Item #
Click the Add To Cart button below if you'd like to reserve this item today. Any other items included in your order will be immediately processed and shipped. We will ship this item separately as soon as it arrives. We will not charge you for this item until it ships and you will incur no additional shipping charges.

Enter your email address in the field below and click the Notify Me button if you'd like us to send you an email when this item becomes available. Although you will be immediately notified when we have stock on hand, we will not reserve any units for you; you must return to our website and place an order.

Your Email:
Just enter your email address below and we'll let you know when the product you are looking for becomes available!

Item Code:
Your Email:
Email Specials
Subscribe to our newsletter feed.
Newsletter Tips & Tricks! New Products!
Discounts & Promos!
June 22, 2016
"I would like to thank Marine Depot for their good deals and the wealth of information about each product they hold and for the excellent customer service."

June 20, 2016
"Very nice website. Easy to find products I am looking to purchase. Lots of good information about the various products and aquarium guidance in general."
Dave K

June 17, 2016
"Website is very user-friendly and checkout was easy and fast. My husband raves about you guys so I am super excited to surprise him with this gift!"

WIN REEF BRITE LIGHTS! Sign up for hot deals, helpful how-to videos and a chance to win a T5 Retrofit Kit and LED Strips!