Answer:
I run cold and hot, I look blue but am red. What am I?
Light me up in backyard gatherings
I lose my head in the morning and regain it back at night. What am I?
I save lives on the ground and in the air. What am I?
Part carbon part water I am poison to the fishes. Many falsely claim my name I am the pause that refreshes.
No matter how little or how much you use me, you change me every month.