Questions about under-tank sumps

[paulamrein]

For those with under-tank sumps. What would you rate the noise level at. Are you hearing a hum from the pump that may be alittle louder than you water sounds? I'm trying to gauge it to my noise and see if it's the nature of having the under-tank sump or it is something I can fix. Currently I have a gen-x 40 I believe it's rated at 1200gph. 125g tank with a 30 gallon or so sump.
Next Question when it comes time to do water changes do I draw the water from the tank or do I change the water in my sump?
The sump concept is still very new, so forgive me for obvious questions.

 

[reefnut1]

The pump you have can be a little loud. You might try a mag 12 in sump style pump. I had that for quite a while and it was quiet for me.
You can remove your old water either way, but it is probably better to take it from your sump and add it there.

 

[scbadiver]

We built a stand for my buddy Jeff's tank with the sump underneath. What we did to minimize noise was line the inside of the stand with sheets of 1 inch thick styrofoam sheets and placed the pump on an old mouse pad. Sitting right next to it you can barely hear anything. He is running a small Iwaki pump and a Euro-reef skimmer under there.