Photo: Green Yoshi · CC BY 3.0
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Aquarium gravel vacuum and siphon
Pick a bulb-start siphon for 10–20s, a longer hose or faucet-hookup when buckets suck, and a narrow tube for nanos and sand. This is the tool page; water-change volume lives on the husbandry guide.
Which tool, not another water-change tutorial
A gravel vacuum is a wide rigid tube, a length of hose, and a way to start the siphon. Waste lifts; gravel falls back. You are choosing diameter, hose length, and start method. How much water to remove (25–30%, about 5–6 gallons from a 20) lives on how to do a fish tank water change. This page is which tool to open first.
You need a bucket that has never seen soap, or a faucet-hookup system that skips the bucket. Write FISH on any bucket. Mouth-start is how people get tank water they did not want to taste. Buy a primer bulb or a self-priming tube instead.
Match the tube to the tank
For most 10–20 gallon community tanks, a medium or ~10-inch rigid tube with a bulb and about 6 feet of hose is the daily driver. The bucket sits on the floor, lower than the tank. Pinch the hose if flow is too fast around fine plants.
Longer hose or a Python-style faucet changer earns its keep on 29–55 gallon tanks, upstairs stands, or anyone who is done carrying five-gallon buckets. The faucet adapter has to fit your sink; check before you commit.
Sand is different from gravel. Hover the intake just above the sand so mulm lifts and sand settles. Plunging like you would in coarse gravel will send substrate into the hose. A narrow nano siphon is easier in 5–10s and tight planted layouts.
Electric vacs and what this tool is not
Battery or electric no-bucket cleaners can spot-clean large tanks without a full drain. Treat them as optional helpers, not a replacement for removing and replacing water. Dissolved waste still needs a partial change on a schedule checked with a test kit.
The picks below are a bulb-start siphon for typical 10–20s, a faucet-hookup changer when buckets are the pain point, and a mini tube for nanos and sand. A broader search sits under that if you need another length. We may earn a commission if you buy. See the affiliate disclosure.
What we would buy
Aqueon Siphon Vacuum Gravel Cleaner with bulb, Large 10-inch
Bulb-start rigid tube and 6-foot hose sized for community 15–55s, which covers a typical 20 into a floor bucket. Primer bulb means you skip mouth-starting. Same style of tool the water-change guide assumes.
On a true 10-gallon, a shorter medium tube empties slower and is easier around plants; this 10-inch still works if you pinch the hose to slow flow. Clip the hose to a FISH-only bucket. Ideal range on the listing is 15–55 gallons.
See this listingPython No Spill Clean and Fill, 25 foot
Faucet-hookup gravel tube and hose. Drain and fill without buckets. The usual upgrade once you are tired of hauling 5 gallons across the kitchen, or when the tank sits a hallway away from the sink.
Skip this on a 20 if a bulb siphon and a FISH-only bucket already work. Confirm the brass adapter fits your faucet. 25 feet covers a kitchen-to-stand run; 50 is for the basement tank. Same listing we open on the water-change guide.
See this listingFluval EasyVac Compact gravel cleaner, Mini
Narrow tube for 5–10 gallon tanks, shrimp setups, and planted nanos where a fat 10-inch vac is clumsy. Quick-start siphon and a gravel guard help on sand when you hover instead of plunging.
Use this when the big vac empties a nano too fast or will not fit between stems. Hover on sand; do not drive the tube in. Skip a second vac if your medium siphon already reaches the spots you care about.
See this listing
Frequently asked questions
What size gravel vacuum for a 10- or 20-gallon tank?+
A medium or ~10-inch rigid tube with a primer bulb and about 6 feet of hose covers most 10–20s into a bucket on the floor. Oversized tubes empty a 10 too fast and are harder to aim around plants.
Do I need a Python-style faucet water changer?+
Not on day one. A $15 siphon and a FISH-only bucket are enough for a 20. Upgrade to a faucet-hookup hose when you are tired of hauling 5–6 gallons, or when the tank is a 29–55 upstairs from the sink.
How do I vacuum sand without sucking it into the bucket?+
Hover the tube just above the sand. Do not plunge the way you do in coarse gravel. A narrower nano siphon gives more control in 5–10 gallon tanks and planted layouts.
Are electric no-bucket gravel vacuums worth it?+
Optional for spot-cleaning large tanks. They are not a substitute for a real water change. You still need to remove and replace water on a schedule; see the water-change guide for 25–30% targets.