Brown spots and tips drying need help new in hydro

[romuros]

i had 2 lights cycling just in the beginning when they sprouted now they are both on plus i have 400MH beside for mothers and clones(which i still didn't decide if i will use or will just go with seeds as i am used to).
On beginning there was fault ppm meter. with new one i get constant reading 1,9mS minus water EC which is 0.42 in my case.
I will try reducing feeding cycles and carefully watch babys to see where is my sweet point.
But anyway they grow so fast now that is unbelievable (for me )
Will post some pics tomorrow as lights go off.
Will also take some pebbles out and soak them in RO water to see if they are causing ph swing. I still have to adjust it every day as go from 5.2 to 5,8 and next cicle to 6.1.

 

[romuros]

hI

Few update on my grow.
Looks like PH is stabilyzed since i omly have to adjust it on two days from 6 to 5.2. EC is also stable at 1.5 mS. I am now watering them once a day once a day 15 minutes before lights goes on.
They are now 5 days into 12/12.
Only thing thats bother me are those giant leaves that block lights to lower branches.
Should i remove them some or it's better to leave as it is. Also i was thinking to remove all lower leaves to get more air circulation at the bottom.
How they are looks to you?

 

[TheArchitect]

Removing a few large upper fans, and the lower junk, is always a good idea, just don't get too out of control...

 

[Hydro-Soil]

Trim everything from the third node on each branch, down to the base of the stem. Those big leaves won't be shading anything anymore and you won't have any larf at harvest time.

Stay Safe!