Buying task · Water changes and testing
Water changes and testing
How often to change water, siphon vacuum or faucet water changer, faucet fit, conditioner on refill, and why free-ammonia monitors and test kits read differently.
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Short answer
For a small tank, a siphon gravel vacuum and a bucket do the job. For a larger tank within reach of a sink, a faucet water changer drains and refills without buckets; check that it fits your faucet and add water conditioner as you refill. Test water with a kit that answers your question: a liquid kit for pH, ammonia, nitrite and nitrate, or a continuous monitor for free ammonia, which reads differently.
Why water changes matter
The Merck Veterinary Manual lists monitoring water quality and a regular schedule of cleaning, water changes and filter replacement as part of preventive fish care, and says new water should be dechlorinated.[1] Its maintenance table gives a water change every two weeks, with the amount depending on how heavily the tank is stocked.[2] Python, which makes faucet water changers, recommends 5 to 10% every other week for its users.[3] That is one maker's advice, not a rule for every tank.
The decisions, in order
1. Siphon or faucet changer. A gravel vacuum is a wide tube on a hose: it lifts waste from the gravel as water siphons out into a bucket. Aqueon says its siphon vacuums are primed by moving the intake tube up and down, and come in sizes from a mini 5-inch tube to a large 16-inch tube.[4] A faucet water changer attaches to a sink faucet instead. Python says its No Spill Clean and Fill drains and refills an aquarium without buckets,[5] and Aqueon sells its Water Changer in 25-foot and 50-foot lengths, with a multi-connection faucet adapter.[6]
2. Size and reach. Aqueon lists its mini vacuum, with a 6 ft hose, for 1-5 gallon aquariums.[4] For a faucet changer, measure the path from the faucet to the tank and choose a length that reaches.
3. Faucet fit. Python says its units come with a 69HD brass faucet adapter for female- or male-threaded faucets once the aerator is removed, and that some faucets need a MABA or FEBA adapter.[3] Aqueon points buyers to a diagram of compatible faucet types.[6] Check your faucet before you buy.
4. Conditioner on refill. Python recommends adding a water conditioner during refill.[5] Merck says new water should be dechlorinated.[1]
5. Testing. API says its Freshwater Master Test Kit measures pH, high range pH, ammonia, nitrite and nitrate with seven test solutions.[7] Seachem's Ammonia Alert works differently: it continuously detects free (un-ionized) ammonia, responding in about 15 minutes to rising levels and about 4 hours to falling ones.[8] Seachem notes that 0.02 mg/L free ammonia equals 3.6 mg/L total ammonia in freshwater at pH 7.0, which is why the two readings cannot be compared directly.[8] Seachem also says the monitor is not recommended at acid pH.[8]
Every page on water changes and testing
Guides
- Faucet water changers: how Python and Aqueon systems fit your sink
- How to prime a gravel vacuum (without using your mouth)
- Free vs total ammonia: why two test readings disagree
- Aquarium maintenance checklist: daily, routine and periodic
Comparison and shortlist
- Python No Spill Clean and Fill vs Aqueon Water Changer
- Water-change tools and test kits: the siphon, changers and tests in our catalog, with the variant to choose
Tank pages
How to choose
Tank size and distance to a faucet decide most of it. A nano tank needs only a small siphon and a bucket. A large tank near a sink is where a faucet changer saves the most carrying.
The water-change shortlist adds Aqueon's 25 ft Water Changer, the API Freshwater Master Test Kit and Seachem's Ammonia Alert.
Key terms
Water change, aquarium test kit, pH, nitrite, nitrate, nitrogen cycle and continuous ammonia monitor.
Everything in this topic
Guides
- Faucet water changersHelps you check that a Python or Aqueon water changer will connect to your faucet and reach your tank before you buy one.
- Free vs total ammoniaExplains why a continuous ammonia badge and a liquid test kit give different numbers, so you can read each one correctly and know when to act.
- How to prime a gravel vacuumGets a siphon running on the first or second try, and helps you pick a vacuum size for your tank.
Comparisons
- Python vs Aqueon water changerHelps you pick between the two faucet water changers by faucet fit and hose length, and shows what to confirm before buying either.
Shortlists
- Water-change tools and test kitsShows which water-change and testing tools fit your tank and routine, and what each maker's own documentation does and doesn't confirm.
Common questions
Will a Python fit my kitchen faucet?
Python says its units come with a 69HD brass adapter for female- or male-threaded faucets after you remove the aerator, and that some faucets need a MABA or FEBA adapter. More in Python vs Aqueon water changer
Which is longer, Python or Aqueon?
Both are compared here at 25 ft. Aqueon sells its changer in 25 ft and 50 ft sizes; measure the hose route from faucet to tank, not the straight-line distance. More in Python vs Aqueon water changer
Do I need water conditioner when refilling with a water changer?
Python recommends adding a water conditioner during refill, and Merck says new water should be dechlorinated. More in Python vs Aqueon water changer
How much water should I change?
Python recommends 5 to 10% every other week for its users; Merck's general schedule is a water change every two weeks, with the amount depending on stocking level. More in Python vs Aqueon water changer
Which one drains faster?
Neither maker publishes a flow rate, and we do not test products, so we can't say. More in Python vs Aqueon water changer
Will a Python water changer fit my faucet?
Often, but not always. Python says its units come with a 69HD brass adapter for male- or female-threaded faucets once the aerator is removed, and that some faucets need a MABA or FEBA adapter. More in Faucet water changers
Do I still need water conditioner with a faucet water changer?
Yes. Python recommends adding a water conditioner during refill, and the Merck Veterinary Manual says new water should be dechlorinated. More in Faucet water changers
What length of water changer do I need?
Measure the path the hose will take from the faucet to the tank, around corners and doorways, and add some slack. Aqueon sells 25-foot and 50-foot sizes. More in Faucet water changers
Questions
How often should I change aquarium water, and how much?
The Merck Veterinary Manual's maintenance table lists a water change every two weeks, with the amount depending on how heavily the tank is stocked. Python recommends 5 to 10% every other week for its users; that is a maker recommendation, not a universal rule.[2][3]
Will a Python water changer fit my faucet?
Often, but not always. Python says its units come with a 69HD brass adapter for female- or male-threaded faucets once the aerator is removed, and that some faucets need a separate MABA or FEBA adapter. See the faucet water changer guide.[3]
Do I need water conditioner when refilling from the tap?
Yes. Merck says new water should be dechlorinated, and Python recommends adding a water conditioner during refill with its No Spill Clean and Fill.[1][5]
Why does my ammonia monitor disagree with my test kit?
They may measure different things. Seachem's Ammonia Alert reads free (un-ionized) ammonia only, and Seachem notes that 0.02 mg/L free ammonia equals 3.6 mg/L total ammonia in freshwater at pH 7.0, so a free-ammonia reading and a total-ammonia reading cannot be compared directly. See free vs total ammonia.[8]
What does the API Freshwater Master Test Kit test?
API says it measures pH, high range pH, ammonia, nitrite and nitrate, using seven test solutions.[7]