Do I need chemical filtration if biological is established?
Written by
Hoang Long
Reviewed by
Prof. David Walsh, Ph.D.While biological filtration converts ammonia and similar toxins, it does not "deal" with dissolved toxins, medicines, and heavy metals. Speciality resins and activated carbon adsorption. This is done in a manner that complements biological filtration.
Medications & Antibiotics
- Absorbs residual treatments after fish disease recovery
- Prevents prolonged antibiotic exposure harming bacteria
- Removes copper-based medications completely
Organic Compounds
- Eliminates tannins from driftwood that discolor water
- Adsorbs phenols causing unpleasant odors
- Removes algae byproducts during bloom events
Heavy Metals
- Traces of copper from pipe corrosion
- Zinc from tank decorations
- Lead contamination from water sources
*Activated Carbon:*. Activated carbon is the most common of the chemical media in use. Due to its porous construction, it possesses enormous surface area for adsorbing impurities from the water as it passes through the filter chamber. One gram of good carbon offers over 500 sq m of surface with which the usual impurities will readily combine, and saturating takes place in a month or so.
Use chemical filtration temporarily during specific situations. If you've had sick fish and medicated them, run carbon for 48 hours to remove any residue. Use phosphate removers when trying to combat an algae bloom to prevent it from receiving a nutrient source. If your tap water contains heavy metals, run chemical media when changing your water. Never run chemical filtration without a reason.
Remember that biological filtration is the ever-present foundation. Make chemical media an adjunct, not a replacement. Continuous carbon use will eliminate trace elements that benefit both plants and fish. It will rob corals of the nutrients they need in reef tanks. Use chemical filtration only for targeted applications.
Position the chemical media correctly in your filter. Chemicals are easily washed out, so ensure they are placed after the mechanical filtration to prevent clogging. If you have a canister filter, the chemical chambers should come before the biological media to reduce the risk of bacteria and other colonies being affected by any chemical leakage. Always rinse your new media in your tank water before using.
If you are using chemical filtration media, monitor your water quite closely and conduct tests for the target substances before and after application. Always supervise your fish while doing so, and have the chemical media readily available as a precaution to remove it in case of unusual fish behavior. This is to avoid stressing any sensitive fish.
Read the full article: Understanding Aquarium Filtration Systems
