are there any 'reasonably' quiet air pumps

[Ca++]

You can spend a lifetime changing pumps, but there are no bldc rotaries yet.

Look at it like this. If your V8 is loud, you don't buy another V8. You work on the exhaust and inlet, motor mounts and bay noise insulation. Just buying the V8 and expecting it to be quiet, is futile. Though people constantly believe it's possible, for entire lifetimes.

I know there is a thread in this. It might even be mine
edit https://www.icmag.com/threads/fridge-motor-air-pump.18126931/page-3#post-18798172
I can't hear mine in the dead of night. With the pipe a an inch from my ear, I get a smooth flow of air, devoid of any pulsing

 

[zachrockbadenof]

Active Aqua, the one and only place for air pumps and chillers.

i bought the '2' pack and seemed to work well for the 1st grow- now into my 2nd grow and yesterday in checking the water didn;t see any bubbles... so figured the pump took a shit... turns out the pump was fine, the air stones i guess were clogged - replaced em and all is good... just in case, i bought a dozen on amazon to have as spares as they don't last much past 1 grow

 

[Ca++]

Two ways they block. From inside, or outside.
Generally it's snotty tanks, which suggests they are not working. Nothing should be growing in there, and if it is... well they ain't working like they should.
Some sort of chloride added occasionally will help. It can work alone, so the pump is then just maintenance between treatments.

Calcium Chloride or Potassium Chloride are the better choices, but Sodium Chloride is a household product. Bleach. Just don't buy thick bleach, as the thickening agent to make it cling to the toilet bowl or tiles, is death to our plants. You need thin bleach. People presume thin bleach has less bleach in it, but no, it's just bleach with no snot added.

 

[zachrockbadenof]

yep... its gotta be on the inside of the small round balls- the outside is clean as a whistle... i will go 12/12 in about a week... at that time i will drain the water and put in clean water... i have to say these vevor hydro pots, i think the 8set with everything included cost like 139 bucks - not a bad deal- no reservoir , so i have to check em every day, but it takes no time, and i can feed/amend the water of each of em (only using '4') ...