+1 to Heera! Not everyone is aware of this, and if you live in a warm area the concern is even higher.
As for the skimmer question, it really depends. Microbubbles are primarily a cosmetic issue, though I have heard one person state health reasons. More on that in a moment.
When bubbles of any size pop, they send a tiny drop of water flying. Over time, this can coat the lights or lid with salt and decrease the light getting through. They also can lead to salt creep on the edge of the aquarium.
The health issue I have heard but have not verified is that the bubbles can degrade a fish's slime coat over time. Again, I do not know the accuracy of this, but better safe than sorry!
Someone stop me! Please! But... not just yet...
55 Gal Tropical FW
55 Gal Mixed Reef