We get a lot of freshwater (FW) water change questions in-store, so let's clear up the common myths and show you exactly how it's done.
Myths to Bust
You do not need to remove fish during a water change
You do not need to scrub down and disinfect the whole tank — never use chemical cleaners on any surface a fish tank touches
It's not time-consuming or difficult once you have the right tools
What You'll Need
A net for floating debris
An aquarium-safe scrub brush or scraper — never a household sponge or scrubber, which may carry cleaning chemical residue
A gravel vacuum: plain tube style (Python), self-starting valve style (Aquatop), or squeeze-bulb style (Fluval) all work equally well
Step-by-Step
Scrub the glass and silicone first (careful not to gouge the silicone itself) while filters are still running, so they trap the loosened debris
Turn off filters (canister/hang-on-back) and heaters before starting the siphon, so nothing runs dry or gets exposed to air — sponge filters can stay running since they're air-driven with nothing to damage
Bucket must sit lower than the tank for gravity siphon to work; secure the hose end in the bucket before starting
For plain tube siphons: submerge, fill with water, lift above the waterline repeatedly until flow starts
For self-starting valve types: submerge and shake up-and-down to prime the siphon
Non-planted gravel: run the vacuum tip through the substrate to swirl and lift debris; pinch the hose to let gravel drop back down if too much gets pulled up
Planted tanks with aqua soil: don't vacuum into the substrate directly — wave your hand above the soil to lift detritus and broken leaves into the water column, then vacuum from there
How Much and How Often
10% weekly is the standard recommendation; cap any single change at 20%. If correcting a serious water quality issue, 10% daily over 5 days is safer for fish than one large 50% change.
Ready to build your water change routine? Shop gravel vacuums and aquarium-safe cleaning tools at natureaquariums.com.
