brown spots are spreading from last week (young plants)

i have a problem guys who don't stop from last week , this are my 2 weeks young plants
photos 1 week ago :

photo after 2 weeks :


this are Northern lights under 600w hps , distance from cooltube is around 50cm , temperature 28 Celsius.

what should i do? they are appearing on random leafs on random plants ( 3 of 5 have this)

soil/nutes/water/etc?

It's actually not random leaves it just seems like it,iI'm sure it started from older lower leaves,but i think your PH is too high and has been for too long.Time to break out the foliage spray and fresh clean water.

they were first in cheap soil , and 2 days ago i transplanted in biobizz ALL MIX soil with perfect ph , i didn't add any nutes just water with ph 7.4 (in 1 week i will order a ph meter and ph down and up solution).

HotShot7414 said:

It's actually not random leaves it just seems like it,iI'm sure it started from older lower leaves,but i think your PH is too high and has been for too long.Time to break out the foliage spray and fresh clean water.

Click to expand...

yes you are right , first are the first seth of leafs than random, , i have biobizz grow , bloom , topmax , and bioheaven, . should i spray with one of them or just water? the lights need to be CLOSED or ON when i do thisi?