No flow or no restart
Note when the flow stopped: right after cleaning, after a power cut, or on its own. After cleaning, check first for air trapped in the pump and for a part put back the wrong way; after a power cut, a canister may need priming again; on its own, check the intake strainer, the hoses and the impeller for debris. Unplug the filter before you open it, and do not leave a pump running dry.
For a Fluval 107 or 307, the 07 manual gives separate steps for reopening the AquaStop valves and for priming again after the hoses lose their vacuum. A Seachem Tidal primes itself, so its steps are different.
Rattle, hum or vibration
First find where the sound comes from: the pump, the filter body, a hose touching the glass, the lid or the cabinet. A filter or hose resting against something rattles more often than a worn motor does. Air trapped in a canister gurgles and rattles: rock the canister gently and run its priming steps again. A grinding pump usually has sand or debris around the impeller: unplug it, take the impeller out and rinse it and its well. Keep the vents clear and never wrap a pump in foam or cloth to quiet it. If the noise stays after those checks, ask the maker about your model.
Leak, damaged housing or wet connection
Never reach for a wet plug. The Aqueon heater and Fluval 07 manuals give the same order: if a plug or socket gets wet, do not unplug it; switch off the fuse or breaker that feeds it, then unplug and check the socket for water. If a device falls into the tank, unplug it before you reach in. Work from a dry spot, and call an electrician if you cannot cut the power safely.
Then stop the leak: close a canister’s valves, or lower the water below the lip of a hang-on filter. Drips at a canister’s head usually come from the main seal or a hose fitting; the 07 manual shows how to inspect its motor-head gasket and which lubricant to use. A cracked housing or a damaged cord means the unit is finished: replace it rather than patching it. Dry connections and drip loops
Temperature differs from the setting
Compare the heater setting with a separate thermometer, and note the room conditions and whether the unit is operating. Aqueon’s Pro heater manual asks for 24 hours of running before you judge a heater, warns that many thermometers are not accurate, and then lists what to check: the setting, power, the minimum water line, water flow around the heater, a tank size within its range and lime scale. Unplug it and let it cool before you lift it out.
The heater sizing guide explains why a cold room needs a stronger heater. If the heater is damaged, or still misreads after these checks, stop using it and contact the maker. The temperature your fish need is on each one’s care page.
What to tell the maker’s support
- The exact model and wattage from the label, and the country you bought it in.
- What happened and when it started, including any recent cleaning or power cut.
- What you checked and what changed.
- The part you need, named as in the manual’s drawing.
Each equipment page links its maker’s manual. For routine cleaning see filter maintenance; for fish in distress, a vet who treats fish can help.