Yes, filtered water can be used safely for reef tanks, and is often preferred. Using filtered water is a crucial step in maintaining a healthy reef aquarium environment.
Here's why and what to consider:
Why Filtered Water is Important for Reef Tanks
Unfiltered tap water often contains substances that are harmful to sensitive reef tank inhabitants, including:
- Chlorine and Chloramine: These are disinfectants added to municipal water supplies and are toxic to fish and invertebrates.
- Heavy Metals: Copper, lead, and other heavy metals can accumulate in a reef tank and harm corals and other organisms.
- Phosphates and Nitrates: These nutrients can fuel algae blooms, which can outcompete corals for resources and disrupt the delicate balance of the reef ecosystem.
- Silicates: These can contribute to diatom blooms, another type of undesirable algae growth.
Types of Filtration Systems Suitable for Reef Tanks:
Several filtration methods effectively remove these harmful substances:
- Reverse Osmosis (RO): RO systems force water through a semi-permeable membrane that removes a wide range of contaminants, including minerals, metals, and organic compounds. This is a widely used and highly effective option for reef tanks.
- Deionization (DI): DI systems use resin beads to remove ions from the water, resulting in ultra-pure water. DI is often used in conjunction with RO to further purify the water. RO/DI units are a common and highly recommended choice.
- RO/DI Systems: Combining Reverse Osmosis and Deionization offers the best of both worlds and delivers the purest possible water for your reef tank.
Important Considerations:
- TDS Meter: A Total Dissolved Solids (TDS) meter is essential for monitoring the quality of your filtered water. A TDS of 0 ppm (parts per million) is ideal for reef tanks.
- Regular Filter Maintenance: Filter cartridges and membranes need to be replaced regularly according to the manufacturer's recommendations to maintain optimal performance. Neglecting filter maintenance can lead to a buildup of contaminants and reduce the effectiveness of the filtration system.
- Remineralization (Sometimes): RO/DI water is so pure that it lacks essential minerals. While some reefers add back certain minerals through water changes with reef salt mixes, others prefer to use tap water for top offs and water changes to get the added minerals. Be cautious and monitor your water parameters closely.
- Source Water Quality: The quality of your tap water will affect the lifespan of your RO/DI filters. If your tap water is heavily contaminated, you may need to replace filters more frequently.
In summary, using filtered water, ideally from an RO/DI system, is highly recommended for reef tanks to remove harmful substances and maintain a healthy and stable environment for your corals and other reef inhabitants.
