Some leaves curling and some twisting.

Having some issues with my girls that are on day 15 after breaking ground. I suspect that I may have a magnesium issue because the middle veins of leaves are a very light in color. The leaves are also curling over especially on the ends and some of the leaves are also twisting. My soil ph seems to be around 7.0 Not sure if I should try to lower my ph or If I should consider adding calmag. I started out using some reverse osmosis drinking water from the store with foxfarm nutes that I mixed at about 1/3 strength of the feeding schedule. Maybe this is where the mg deficiency came from? I havent had any burning of leaves or yellowing at all but I am still very new to the indoor thing, as this is my first run at it. Any knowledgable advice would be appreciated.

Thanks
PurplePride

yep if you are useing RO water you need calmag
and water with 6.5, dont worry to much about the soil ph to much watch what your putting in it
kick up the nutes they look hungry

But don't overdo it. Learn to 'read' your girls, when their not doing much I don't give them much, if they're vigorous from the start I feed them almost full 'dose' from the get go. If it's really hot they need more water than food so I'll feed even a vigorous plant a half solution on a hot day. Just use common-sense & keep it simple, & you'll be rewarded like the rest of us

Its definately not hot. My temps are ussually 75 for a high during the day and 68 for a low at night. My air cooled hood stays nice and cool with the fan I got so i'm good there. I fed them today and bumped up the nutes a little. Using Grow Big and Big Bloom. I mixed with some of my tap water and adjusted the ph down to 6.5 afterward. My calmag wont be here till tuesday so I had to go without for this feeding. Hoping the tap water helps a little till calmag gets here. These girls started out really fast and have slowed down a little the last couple days. Although I am still impressed for 2 weeks from seed. Thanks for the advice, its appreciated...

-PurplePride