Can plants replace filtration systems?
Written by
Hoang Long
Reviewed by
Prof. David Walsh, Ph.D.Aquarium plants offer tremendous use, but can't replace proper filtration. While they may consume nitrates and some nutrients, they do not break down toxic ammonia, and no mechanical cleaning is involved. Your filtration is a huge part of the waste processing that plants cannot do alone. Your fish need plants and proper filtration to thrive truly.
Ammonia Processing
- Plants don't convert toxic ammonia from fish waste
- Only beneficial bacteria in filters handle this critical task
- Ammonia kills fish within hours without biological filtration
Mechanical Cleaning
- Plants don't remove solid debris floating in water
- Uneaten food and fish waste accumulate without filtration
- This debris decomposes and creates toxic conditions
Oxygenation
- Plants consume oxygen at night during respiration
- Filters provide constant surface agitation for gas exchange
- Without filters, oxygen depletion can suffocate fish
Plants function best as nitrate reducers in a mature system. They consume nitrates that the power of "water changes" cannot remove. Fast-growing plants, such as hornwort, positively thrive. However, in even the most densely planted tanks, a filter is usually necessary to handle the initial waste. I have tried to maintain planted tanks that did not have a filter. In all cases, ammonia produced exceeded the safe level.
1. What load is the biological load, to be exact? A sufficient load is produced by the fish to require filtration, regardless of the plants. Some goldfish produce more ammonia than twenty plants could absorb. The filters contain billions of bacterial cells that respond immediately to this waste. The plants would not stand a chance.
Combine in a tank with plants, and use appropriate forms of filtration for optimal effect. In a planted tank, choose filters with variable-adjusted sluices, so that the rapid flow may not destroy the tender foliage. Avoid all intakes surrounded by plants and refuse; ensure that the filter does not trap carbon dioxide on its filtering surface or capture bits of wood and other materials that plants need for growth. The botanical and mechanical systems should complement each other.
Interconnected, Maintain Both Systems for Mutual Benefit. Always make it a point to prune all your plants of decaying leaves, as they putrefy and pollute your water. Clean the filter's media in the tank water to preserve the good bacteria. Test your water weekly to confirm everything is balanced. These interrelated systems create the healthiest aquariums around.
Read the full article: Understanding Aquarium Filtration Systems
