skimmers question?

[wtjoe]

hello
i've got a stupid question.
i have 125gal tank
i have a skimmer red sea classic
is it normal that everytime i change the water or move the sand the skimmer goes crazy over flows have to empty the bottle serveral times that comes out for the skimmer that holds the dirty water. i never had the problem before.
is it broken or it is normal.
thanks

 

[TippyToeX]

That's not a stupid question.

Does the water level changed quite a bit after you have done a water change?