Micro Bubbles After Water Change...

Hey everyone,
I was just curious to why my skimmer produces tons and tons of micro bubbles after I do a water change. They eventually go away but I just wanted to know why.
Thank you.

 

I noticed the same thing it seems to be better sence i mix my water a week ahead of time i have adopted the trash 30 gallon with the power head theroy about 2 months ago and probly has been the best thing ive done in this hobby so far but the old lady dont like 2 garbage cans in the laundry room lol

but mine will go nuts for 12 hours before it calms down i just open the valve all the way before i add the water and reset it in the morning the way i see it if the tanks inhabitance are ok i dont fuss