GPH too high after raising a canister above the stand
Raising a canister filter reduces the vertical lift the pump must overcome, so its flow can increase. Check the actual current, verify the…
Troubleshooting
Help matching aquarium filters and pumps to tank size, bioload and noise tolerance.
Flow & Size
Troubleshooting
Air Pump Too Loud for a Bedroom Tank: Causes and Fixes
A loud aquarium air pump is usually caused by vibration, a clogged air stone or tubing, an unstable surface, or a worn diaphragm—not simply…
Air stone barely bubbling: causes and fixes
If your air stone is barely bubbling, check the stone and airline first, then look for leaks, kinks, excessive depth, and a weak or failing…
Aquarium filter making a rattling noise
A rattling aquarium filter is usually caused by trapped air, a dirty or damaged impeller, a clog, or incorrect water level. Follow these…
Aquarium Filter Not Flowing: Causes and Fixes
An aquarium filter that stops flowing is usually dealing with clogged media, a blocked intake or hose, trapped air, low water, or an…
Canister filter O-ring leak: causes and fixes
A canister filter O-ring leak is usually caused by a dirty, dry, twisted, damaged, or incorrectly seated gasket. Unplug the filter, stop…
Canister filter will not prime
If your canister filter will not prime, unplug it first and check the filter media, hoses, seals, setup, and water level in order. Most…
Canister intake sucking gravel
If your canister filter is sucking gravel, unplug it first, then check the intake height and strainer. A missing or damaged intake guard,…
Cloudy water after a filter change
Cloudy water after a filter change is often temporary, but the cause matters. Learn how to distinguish loose debris, a bacterial bloom,…
Filter outflow blasting fish into the glass
If your aquarium filter is blasting fish into the glass, redirect or diffuse the outlet before replacing the filter. These practical fixes…
Filter Too Strong for Bettas? How to Reduce Aquarium Flow
A filter that is too strong can make a betta hide, struggle to swim, or avoid parts of the tank. Reduce the output first, then check the…
Hang-on-back filter leaking down the tank: causes and fixes
If water is running down the outside of the aquarium from a hang-on-back filter, unplug it and find the exact leak before restarting it. A…
Impeller Magnet Coming Loose: Causes and Fixes
If the magnet on your aquarium filter impeller is coming loose, unplug the filter and replace the complete impeller assembly in most cases.…
Sponge filter collapsing or clogging
A sponge filter usually collapses or stops flowing because the sponge is clogged, the airline or lift tube is blocked, or the sponge has…
Salt creep clogging a marine HOB
Salt creep is dried salt left behind by splashes and evaporation. Unplug the HOB, clean removable parts with fresh water, and check for a…
Suction-cup air stone falling off
An air stone usually falls off because its suction cup is dirty, stiff, or being pulled by taut tubing. Clean the mounting surfaces,…