Should the powerhead be left on overnight with the airstone? And should airstone go off in the morning or before co2 goes on as it's quite noisy...Not with just an airstone and powerheads 😉
Does it really bother you? Is the air-pump not stable and-- making a hum or vibration-- because it needs to be put on a piece of styrofoam or other stabilizing surface? I have air pumps in all 4 of my fish-tanks in my den and can barely hear them.You can definitely pull the airstone. I'd leave the powerhead on, but that's me- I like a bit of surface agitation/ flow at all times.