So..what causes a stained liner?

What gets rid of stains? Will brushing the pool get rid of the stains?

If the chemicals stay out of balance will the liner stay stained?

The entire pool is the same yellow/green color, no difference anywhere.

If the chlorine stays in the 5-10 range isn't that too strong to swim in for children?

What will I do differently when the kit arrives?

Really appreciate your knowledge!