How long can I keep water still in a refugium?

[TangReefer]

Hi guys,

Not particularly new to the hobby but new to refugiums. I just setup a 5gal fuge on top of my sump and am currently waiting for the mud dust to settle, apparently should take 2-3 days. However I filled it with tank water, which means it already had bacteria in it. Can that water sit still for these days without going bad or must I circulate it (which will not help with the settling)?

Thanks and cheers.

 

[heathlindner25]

I would pull the mud out and not use it .