RO/DI
400490 · 4 Stage 100GPD
Professional-grade water purification for pristine aquarium water. Waterbox RO/DI Units are engineered to deliver the purest water possible for your aquarium—ensuring the ideal foundation for reef and freshwater systems alike....
Or build it into a bundle — save up to 6% ↓What it is, and who it is for.
Professional-grade water purification for pristine aquarium water.
Waterbox RO/DI Units are engineered to deliver the purest water possible for your aquarium—ensuring the ideal foundation for reef and freshwater systems alike. Available in both 4-stage and 5-stage configurations, each system features a 100-gallon-per-day membrane and premium filtration components designed for long-lasting performance and exceptional purity.
The 4-stage unit includes a sediment cartridge, carbon block, RO membrane, and DI resin to achieve zero TDS (total dissolved solids). The 5-stage unit adds an additional DI resin cartridge for extended filter life—perfect for aquarists who produce large volumes of water or demand maximum efficiency.
How It Works:
Water first enters the sediment cartridge, which removes particulates such as dirt and debris, extending the lifespan of the following filters.
Next, the carbon block removes chlorine, chloramines, and discoloration, protecting both your aquarium and the RO membrane.
The membrane stage then removes over 98% of impurities, including heavy metals and organic compounds.
Finally, the DI resin polishes the water to absolute purity, eliminating all remaining dissolved solids. The 5-stage system doubles DI capacity for longer intervals between replacements.
Key Features:
• 100 GPD (gallons per day) membrane for high output and efficiency
• Dual inline TDS meter to monitor water quality before and after filtration
• Built-in pressure gauge for optimal performance between 60–80 PSI
• Flush kit to extend membrane life and maintain peak efficiency
• Auto shut-off system with float valve for spill-free water production
Whether you’re preparing water for mixing reef salt, performing water changes, or topping off evaporation, Waterbox RO/DI Units provide unmatched purity, reliability, and ease of use.
How to install the Waterbox Aquariums RO/DI system.
Build around the RO/DI.
It's already in your system below. Add the flow, filtration and dosing around it and the discount starts working — tiers climb as the build grows, and the reef meter fills with it.
Pick the right one, not the biggest one
The honest line-up from ato & ro/di. Most buyers reading this page should buy the middle column.
Osmolator 3 ATO
RO/DI
SpectraPure MaxCap RO/DI System with BoosterAsked before checkout
The questions our support inbox actually gets.
Does it ship quickly?+
Orders placed before 2 PM ET on a business day leave the same day. Tracking is emailed the moment the label prints.
What if it's the wrong fit for my tank?+
Return it. 30 days, no restocking fee, refund to the original payment method. Better: tell us your tank first and we'll spec the system for free — half of all returns are sizing problems.
Who handles the warranty?+
We do. Everything carries the manufacturer's warranty and we run the claim for you — one email to us instead of a ticket queue.
How does the bundle discount work?+
Add items in the bundle builder: 2+ items saves 5%, 3+ saves 8%, 4+ saves 12%, and 5+ saves 15% off the whole system, applied at checkout.