I,ve just got a Deltec mce600 second hand for my tank which is 175 ltrs, would I need to run it all the time with it having alot more capacity than my tank size. Say I put it on a timer and run it for 12 hours a day would this be OK. Its just the wife is moaning about the noise .
I turn mine off of a night time as the tank is in my bedroom. Another option would be to turn down the flow rate of the skimmer (if it has this feature). This will quiten it down considerably. Also you might want to turn it down anyway as you may be getting microbubbles or overskimming and basically just wasting water.
The only other thing you could do is buy some ear mufflers - either for the wife so she can't hear the skimmer, or for you so you can't hear her yapping.