I am kinda new to the wonderful game we all play...

But if I was you I would keep it at 18/6, get a fan in there blowing gently on the young ones to help increase the size of the stem for the long term, keep up the good job on the ph checking, keep the 1/4 nutes until week 4 ish (you'll be able to see where your plants are by then, and they will tell you :thumbsup: ), keep it watering three times a day, but you have to give a buffer and never water in the dark ( as for the buffer 2 hours before and after dark )

Lights come on at 6 am
First water at 8 am
Second watering at 4pm
Third watering at 10 pm
Lights off at 12 pm

You plants might be in shock with all the changing of light patterns, be patient and listen to your new babes, they have alot to say and show you OMG I was amazed what they do for me!

Peace,
Booya