Bubble water whit airstone? ore not?

And it's 9 autoflower in 12.l air pots too much for 120cmx120cm×200cm plan was 5 Nothernlight autoflower and 4 Bcn critical xxl autoflower?

My tap is only 17,8 its that bad?

Okay tanks I'm growing in soil. I hear som talking about you mess with the ph if I use airstone 24 h before watering🤔🤔??

If your using tap water you should let it sit for 24 hours to vaporize off the chlorine. Using an air stone does help. Still check the ppm after. You don't want to use really hard water, over 200ppm right out of the sink.