How do live plants affect water chemistry?
Written by
Kailani Okoro
Reviewed by
Prof. Henry Webster, Ph.D.Natural biological processes, facilitated by aquarium plants, significantly alter water chemistry. They absorb nutrients such as nitrates and phosphates, which lower phosphate triggers for algae growth in aquariums. They produce oxygen during their photosynthesis process, thus improving the quality of water. The roots of the plants can be a great habitat for beneficial bacteria, which aid in biological filtration. When plants are properly maintained, they provide a stable environment that promotes health in fish.
Plants actively decrease pH by utilizing CO₂ during the day. This produces a natural acidity akin to that found in the Amazonian ecosystem. Fast-growing species such as hornwort consume more carbon dioxide. My discus tank maintains a constant pH of 6.8, eliminating the need for artificial buffers, thanks to its heavily planted design. This imitates natural ecosystem processes quite artfully.
Nutrient Balancing
- Prune fast-growers weekly to remove absorbed nutrients
- Rotate plant types for diverse nutrient uptake
- Supplement iron for red plants
- Avoid overstocking to match plant capacity
Photosynthesis Management
- Provide 8-10 hours of light daily
- Add CO₂ injection for dense growth
- Maintain consistent photoperiods
- Position high-oxygen plants near filters
Ecosystem Integration
- Combine with beneficial bacteria supplements
- Use plant-friendly substrates
- Include algae-eating species
- Test water biweekly for nutrient balance
Plant roots create microbial hubs, enhancing biological filtration. The rhizosphere houses nitrifying bacteria processing waste. My planted tank cycles faster than bare setups. This natural filtration reduces ammonia spikes after feeding. Always leave some mulm for bacterial colonies to thrive.
Equalize plant density to avoid nighttime oxygen drop. At night, plants consume oxygen while producing carbon dioxide (CO2). The overuse of plants will cause low oxygen levels. I also add surface agitation and maintain plant density at approximately 70% coverage. This will ensure that oxygen levels are maintained at a consistent level throughout the day, with lower levels at night and higher levels during the day.
Monitor water parameters weekly to verify plant effects. Review nitrate reduction to help with fertilization levels. Monitor pH fluctuations during light periods. Log notes 40% nitrate reduction after floating plants were added. Utilize plants strategically within the system to enhance filtration.
Read the full article: Understanding Aquarium Water Parameters
