First experience

[Mdragger88]

The FC went from 9 at night to 7,5 in the morning.

Sadly, An overnight loss of over 1ppm is a fail -
You have organics (algae) brewing.
This requires the SLAM Process which is impractical at your current cya level (160)
You need to exchange at least 75% of your water to get cya down to around 40 so your slam level is 16ppm - much easier to maintain than the current necessary slam level of 64ppm. FC/CYA Levels

The no drain water exchange outlined in the draining article I posted above is the safest option for replacing that much water especially with all the tile.

 

[jjrapy]

Sadly, An overnight loss of over 1ppm is a fail -
You have organics (algae) brewing.
This requires the SLAM Process which is impractical at your current cya level (160)
You need to exchange at least 75% of your water to get cya down to around 40 so your slam level is 16ppm - much easier to maintain than the current necessary slam level of 64ppm. FC/CYA Levels
View attachment 467392
The no drain water exchange outlined in the draining article I posted above is the safest option for replacing that much water especially with all the tile.

Oh I see now. Also my mom confirmed today that the guy who take care of the pool use some copper sulfate but she doesn’t know how much maybe that’s why the green stains now. Replacing the water will also help with copper?

 

[Newdude]

the guy who take care of the pool use some copper sulfate

Many of the pool store potions have copper. Especially the 5 in 1 type magic potions, but also certain pucks and algecides. In the States, the word Blue anywhere in the name almost guarantees it has copper.

Replacing the water will also help with copper?

Draining is the only way to sucessfully remove copper Hopefully a large drain will remove enough to bring you back below the visible threshold. Unlike CYA, there may be metals in your fill water so the drain doesn't always remove a proportionate percentage.

 

[jjrapy]

Many of the pool store potions have copper. Especially the 5 in 1 type magic potions, but also certain pucks and algecides. In the States, the word Blue anywhere in the name almost guarantees it has copper.

Draining is the only way to sucessfully remove copper Hopefully a large drain will remove enough to bring you back below the visible threshold. Unlike CYA, there may be metals in your fill water so the drain doesn't always remove a proportionate percentage.

Unfortunately yes, but this guy bought pure copper sulfate
Theoretically the algaecide that most stores sell over here are copper free

 

[Mdragger88]

Copper in Pool Water - Further Reading

www.troublefreepool.com