Ok. Here is the update on what happened after I cleaned my filter. I ran the filter overnight and today morning the green water is gone and I can see the bottom of my pool. It is definitely much better.

My pool is not rectangular but a more like distorted 8. So I did some calculations and the rough estimate on capacity of pool is ~22000 gallons.

What is the product you guys recommend increase chlorine ? I mean which brand liquid bleach or liquid chlorine. Also, I am going to start using BBB method and give it a try.

And as Lesiles measured my CYA to zero, what product I need to buy to get it to right level ?

Thanks WaterMom and Carl for you inputs. They give me so much confidence that I can do it right.