You’re using perlite correct? Did you give the perlite and complete drenching of fresh water before putting the plants in? Reason being fresh perlite is very dusty it needs to be flushed throughly. Most likely reaso for fluctuation with ph.
Put plants in full sun if only in the 70’s. 15 off 5 on is ok you can lower it down to 2 minutes on if you can but start with 5 minutes for now. It will take 9 - 14 days for you to see some growth as the plants need to adjust to new enviorement. They will skyrocket after that. That’s when you go to 3/4
nutrients.