There are three important concepts when it comes to caring for your pool: circulation, cleaning, and chemistry.

You notice the blue effect when you have a large volume of water because of the way molecules are slightly absorbing light from the red end of the spectrum. “Light is made up of red, green and blue, the whole spectrum, and we usually see them merged together

Chlorine is added to the water to kill germs, but it does not work right away. If used properly, chlorine can kill most germs within a few minutes. CDC recommends pH 7.0–7.8 and a chlorine concentration of at least 1 ppm in pools and at least 3 ppm in hot tubs.

Use a pool brush to vigorously scrub any pool surfaces covered in algae, including the walls, floors and steps. Apply a green algaecide according to the directions on the label. Let the water circulate for 24 hours, then brush the pool surfaces again. Vacuum or backwash to remove any remaining dead algae.