Reverse Osmosis Systems
Pure water is the foundation of a healthy marine aquarium. Our range of Reverse Osmosis (RO) and RO/DI filtration systems helps you produce high-quality purified water for reef aquariums, saltwater mixing and freshwater top-ups.
Tap water can contain dissolved minerals, nitrates, phosphates and other impurities that may contribute to unwanted algae growth and affect aquarium water quality. Reverse osmosis filtration significantly reduces many of these contaminants, giving you greater control over the water entering your aquarium.
At Rock ’N’ Critters, you'll find TMC V2 Pure RO systems, replacement membranes, sediment and carbon filters, de-ionising resin, TDS meters and essential RO accessories. Whether you're installing your first RO system or maintaining an existing setup, we have the equipment to help you produce cleaner, more consistent aquarium water.
Browse our reverse osmosis systems below:
Why Use Reverse Osmosis Water in a Marine Aquarium?
Water quality is one of the most important factors in maintaining a successful marine or reef aquarium. Although household tap water is treated to be safe for drinking, it may contain dissolved minerals, nitrates, phosphates, silicates and other substances that are undesirable in a carefully controlled aquarium environment.
Reverse Osmosis (RO) filtration removes a substantial proportion of dissolved impurities, allowing aquarists to prepare consistent, high-quality water for mixing marine salt and replacing water lost through evaporation.
For particularly demanding reef aquariums, an additional De-Ionisation (DI) stage can further reduce remaining dissolved ions, helping achieve the 0ppm TDS readings commonly targeted for reef aquarium water preparation.
How Does Reverse Osmosis Work?
Aquarium RO systems typically use several filtration stages to purify incoming tap water:
1. Sediment Filtration – Removes suspended particles such as rust, sand and silt, helping protect subsequent filtration stages.
2. Carbon Filtration – Reduces chlorine and certain organic contaminants that could otherwise damage the RO membrane.
3. Reverse Osmosis Membrane – Uses water pressure to force tap water through a semi-permeable membrane, separating much of the dissolved mineral content from the purified water.
4. De-Ionisation (Optional) – Uses specialist ion-exchange resin to remove remaining dissolved ions, producing exceptionally low-TDS water.
During operation, the RO membrane produces both purified water and a concentrated waste-water stream, which must be directed to a suitable drain.
When Should RO Filters Be Replaced?
Regular maintenance is essential for maintaining water quality and protecting your RO membrane.
Sediment and carbon filters require periodic replacement, while RO membranes and DI resin should be monitored for declining performance.
A digital TDS meter is particularly useful for checking purified-water quality and identifying when the membrane or DI resin may require attention.
For reef aquariums, a final reading of 0ppm TDS is a useful target, although TDS testing cannot identify every possible contaminant.
Complete Your RO Installation
Alongside our TMC V2 Pure RO systems, we stock replacement membranes, sediment cartridges, carbon filters, DI resin, RO tubing, tap connectors and drainage fittings.
For added convenience, explore our automatic RO shut-off systems, designed to help prevent accidental overflowing of water storage containers.
Whether you're starting a new reef aquarium or maintaining an established marine system, Rock ’N’ Critters has the RO equipment and accessories to help you prepare high-quality aquarium water.
For more information on our reverse osmosis systems, be sure to call us today on 01446 737210 or email us at customer-service@rockncritters.co.uk.