No, pumps water only. A submersible pump can only pump what it is submerged in and since there is no air under water......
A pinhole leak or a valve on the line not shutting off properly and introducing air into the water line feed.
Yes, but I would be careful. It could destroy the pump if made of certain materials.If it's a lead pipe or a nonmetal, you're probably fine, and yes, it will remove manganese and magnesium, although the reaction could be dangerous/explosive if proper care is not taken to make sure it works correctly.
wow slow down there!!! adding to much stabelized chlorine over time will add too much cyanuric acid aka stabelizer or (CYA).So this means your pool water is out of balance a lot. red burning eyes,itchy skin are the first signs of improper balance. The only way to reduce cya is to drain out water and replace with new. you can do it yourself or use a pool service, Your check book will answer that for you.You will need a cya test kit although you can buy seperatly or buy with a complete kit which you should have anyway If your CYA is over 100 and approaching 150 then you may have too much CYA in the pool. Granular and tabs used exclusively will cause the CYA to be raised. Alternate monthly between the granular or tabs and 12.5% liq. chlorine. This will increase the time it takes to build the CYA. Or switch over to liq. until the CYA is within acceptable range. You will need to drain the pool pratially to lower the CYA. To do this usually takes a separate submersable pump to which you attach a hose.