BLU 9003: How to Clean an Aquarium Without Cloudy Water

By Ferplast U.K. | Published: 2026-11-03

Category: How-to Guides

A practical fish tank cleaning routine that keeps water clear, using the Ferplast BLU 9003 net and simple gravel cleaning tips to avoid cloudiness.

Quick answer

Clean your aquarium in stages: unplug equipment, skim the surface, vacuum gravel without over-stirring, wipe glass gently, and replace water slowly. Rushing any step—especially gravel vacuuming or refilling—is the most common cause of cloudy water.

Why cloudiness happens during cleaning

Cloudy water after cleaning usually comes from fine debris stirred up by gravel vacuuming or from tap water minerals reacting with tank water. Disturbing the substrate too deeply releases particles that stay suspended for hours. Refilling too fast can also stir up sediment and stress fish.

The fix is not a special product but a slower, staged routine. Let debris settle between steps, and avoid deep gravel disturbance unless you have a specific reason.

Tools that help you work gently

A long-handled net lets you reach the far corners without leaning over and bumping the tank. For gravel, a siphon with a narrow nozzle gives more control than a wide one. Keep a dedicated bucket for aquarium use only—household buckets can carry soap residue that clouds water and harms fish.

The Ferplast BLU 9003 net is available with a 32 cm or 38 cm handle, so you can choose the reach that matches your tank depth. A longer handle means less stretching and fewer accidental knocks against plants or decor.

Step-by-step cleaning routine to avoid cloudy water

1. Unplug equipment and prepare: Turn off the filter and heater. Set aside a clean bucket and your aquarium tools. Mistake to avoid: forgetting to unplug the heater—it can crack if exposed to air during water removal. Double-check that the heater is off before you remove any water.
2. Skim the surface: Use a net to remove floating debris, leaves, or uneaten food. Work gently to avoid pushing particles into the water column. Mistake to avoid: chasing debris too quickly, which stirs the surface and sends particles downward. Skim before you disturb the gravel so floating debris doesn't sink.
3. Vacuum gravel without over-stirring: Insert the siphon slowly and vacuum only the top layer of gravel. Move in sections and avoid digging deep. Mistake to avoid: vacuuming the entire substrate at once—this releases a cloud of fine particles that takes hours to settle. Vacuum no more than one-third of the gravel area per session.
4. Wipe glass and decor gently: Use an aquarium-safe sponge or scraper to clean the glass. Rinse decor in a bucket of tank water, not under the tap. Mistake to avoid: scrubbing aggressively, which can scratch glass or dislodge algae into the water. Rinse decor in tank water to preserve beneficial bacteria.
5. Replace water slowly: Pour new water onto a plate or against the glass to reduce disturbance. Match the temperature and treat tap water before adding. Mistake to avoid: pouring directly onto the gravel, which stirs up sediment and creates instant cloudiness. Add water in several small pours, not one large splash.
6. Restart equipment and observe: Plug the filter and heater back in. Let the tank settle for at least an hour before feeding. Mistake to avoid: feeding immediately—fish can stir up debris while eating, prolonging cloudiness. Wait until the water clears before the next feeding.

Product facts

BLU 9003: Long handle available in 32 cm or 38 cm models. Lets you reach all parts of the tank without disturbing the water as much, reducing the chance of stirring up debris.
BLU 9003