Diatoms in a reef tank are primarily caused by the availability of silicates, which serve as their food source.
Understanding Diatom Blooms
Diatoms are a type of algae characterized by their silica cell walls. They often appear as a brown film covering substrate, rock, and glass in an aquarium. While unsightly, they are a common occurrence, especially in newly established tanks.
The Role of Silicates
According to information from June 30, 2021, diatoms feed off of silicates. Silicates are compounds containing silicon and oxygen. When present in the water, they provide the necessary building blocks for diatoms to grow and multiply rapidly.
Common Sources of Silicates
Diatom blooms are frequently triggered by the introduction of new materials into the tank. As the reference states, diatoms will appear when new rock, sand, and even plastic is introduced into your tank.
- New Live Rock or Dry Rock: These can leach silicates into the water as they cure or equilibrate.
- New Sand or Substrate: Many types of sand, especially silica-based sand, are significant sources of silicates.
- Equipment (Plastic): While less common, some plastic components or glues used in aquarium equipment can potentially leach silicates.
- Tap Water: Tap water often contains silicates, making the use of filtered RODI (Reverse Osmosis De-Ionized) water crucial for reef tanks.
- Salt Mixes: Some lower-quality salt mixes might contain trace amounts of silicates.
Managing Diatoms
While diatoms can grow back impressively quick, they are often easy to remove.
- Physical Removal: As noted, they can be removed with a turkey baster or algae magnet. Blowing them off rocks and substrate allows filtration to capture them.
- Addressing the Source: The long-term solution involves identifying and reducing the source of silicates. Using RODI water, selecting low-silicate sand and rock, and ensuring equipment is aquarium-safe can help prevent recurrent blooms.
- Tank Maturity: Diatom blooms are often a temporary phase in a new tank as the ecosystem matures and other organisms, like beneficial bacteria and algae, begin to outcompete the diatoms for available nutrients and silicates.
In summary, diatoms appear and thrive when silicates are available in the water, with common triggers being the addition of new rock, sand, or certain plastic materials.
