Why am I thinking about getting a new Return Pump?
Well, She Who Casts No Shadow is not happy with the 'humming' noise from the tank. I tried to explain that the main pump is moving about 6.5 tonnes of water per hour, but that made no impression. I must admit, there is a 'hum' coming from the tank, and I think the reason is that we have a cellar in our house, so basically, under the floor there is a gurt big empty space. If you go down into the cellar you can quite clearly hear the tank. It sounds as though something is touching the sump somewhere, but I've checked everything, and the main two things that create any noise are the Return Pump, and a Eheim 1000 pump I have in the Sump to feed the Chiller. With a bit of fiddling I can sort out the Eheim pump, but no matter what I do I can't seem to reduce the noise from the Return Pump. I've experimented by switching things off one at a time and it is the Return Pump that is the culprit. But, will a new pump solve it? If, as I suspect, it's the void underneath that is causing it, then no, it will not, but I have no way of finding out unless I get a new pump.