Airstones oxygenate the water, but the pumps running them can be noisy.
My air pump is very noisy and non-fishkeeping family members are complaining. How can I make it quieter? It has a really annoying rattle and hum noise, which is upsetting the peace of my aquarium.
MATT FLYNN, EMAIL
Some air pumps are quieter than others so that may be the first factor. The second is the power of the pump. Larger air pumps generally make noise than smaller ones.
What airline are you using? Clear PVC 6mm airline is the most common although it can get brittle over time, causing rattling if it touches and vibrates against a cabinet wall. It also becomes stiffer, causing your pump to ‘walk’ across a space until it hits a cabinet wall and itself cause lots of noise and vibration. If using PVC, swap for soft silicone airline.
Non-return valves cause back pressure and noise, but you definitely need these. Some are more supple than others though, which I test by blowing through them to see which one allows airflow the easiest. Try new airline and a new valve, and check that the air filter pad isn’t blocked or restricted.
Where the pump is situated can also be a factor. A cabinet can act like a speaker box, amplifying noise. Try placing a Tupperware container over the pump with a gap underneath to allow air in.
Many air pumps also have provision for vertical mounting, so try that if possible — or you could even hang it with string. Take the contact with hard surfaces away and any noise should be reduced dramatically.
JEREMY GAY