Cleaning your aquarium is essential to fish health and water clarity, but doing it the wrong way can actually do more harm than good. From over-scrubbing filters to using household tools, even well-intentioned aquarists can unintentionally disrupt the delicate balance in a freshwater tank. Here are the top five cleaning mistakes to avoid—and how to do things right every time.
❌ 1. Over-Cleaning or Replacing All Your Filter Media
Your filter isn't just removing waste—it's home to beneficial bacteria that keep your nitrogen cycle running. If you rinse all the media in tap water or replace it all at once, you risk crashing your cycle and spiking ammonia levels. Instead, rinse mechanical filter media like sponges in old tank water and stagger chemical or biological media replacements to preserve bacterial colonies.
❌ 2. Using Soap or Household Cleaning Products
Never use soaps, detergents, or glass cleaners inside or around your aquarium. These chemicals leave residues that are toxic to fish—even in tiny amounts. Always use aquarium-specific tools and cleaners, or a dedicated sponge and hot water only. Magnetic algae scrapers, filter-safe brushes, and gravel vacuums are your best friends for safe cleaning.
❌ 3. Stirring Up Too Much Debris
Cleaning your gravel too aggressively can release harmful gases from anaerobic pockets or cloud the water with detritus. Use a gravel vacuum to gently siphon waste from the substrate, and go section by section. In sand-based tanks, lightly hover over the surface to avoid disturbing rooted plants or beneficial bacteria layers.
❌ 4. Changing Too Much Water at Once
Massive water changes can shock your fish by altering temperature, pH, and hardness too quickly. Unless you're addressing an emergency, stick to 20–30% weekly changes with temperature-matched, dechlorinated water. Gradual adjustments are safer and maintain consistent parameters that your fish can rely on.
❌ 5. Forgetting to Condition Tap Water
Tap water contains chlorine and chloramine that can instantly damage fish gills and beneficial bacteria. Always dose a trusted water conditioner—like Seachem Prime or JBL Biotopol—before adding tap water to the tank. Even top-offs require dechlorination to prevent long-term stress on your livestock.
✅ Clean Smart, Not Just Often
Tank maintenance isn’t just about looking clean—it’s about keeping the internal ecosystem balanced. With the right tools, techniques, and timing, you’ll spend less time troubleshooting algae or illness and more time enjoying a thriving aquarium.
At Charterhouse Aquatics, we stock everything you need to clean safely and effectively—from water conditioners and test kits to gravel vacuums and scrapers.
Clean with confidence. Avoid these common mistakes, and your aquarium will stay beautiful and balanced for the long run.
