Drooping, curling, yellowing leave edges. Should I be concerned?

Hello all, the plant is 7 weeks.The leaves first started to yellow around the edges of the top layers. Now the lower leaves are curled up as if protecting themselves??? I am thinking my lighting is too close to the plants. I have 2X100watt MH and 2X70watt HPS. Waiting on a 250watt HPS for the flowering.

I water once every 2-3 days when I stick a thin wire in soil about 6-7in and it comes up dry. I give it nutes every other watering. So, once or maybe twice a week on nutes. I use purified water, not tap.

Plant is female and I just changed nutes to higher phosphorous and lighting from 18-6 to 12-12 to start flowering.

Thats a wrap with the conditioning. So can anyone tell me why the plant looks unhealthy? I am kinda boggled.

nute burn + may be cal mag diffency, I think, I'm kind of a newbe
what is your PH, and your EC of nuts, what is PH +EC of run off
purified water has cal +mag taken out of it,

Well, I have one meter reading just under 6 and one reading just over. So, 6.0 is a good mean for PH. I am also kinda newbie, so EC?? Do not know what this is.

Was using a watered down MG mixture of 24-8-16. Just switched to 18-24-16.

a plant that size doesent rearly need nuts,
EC reeds how much nutes in the water
MG is real strong 2ml per gal would be max nuts at moment (if any) .
you need to flush water now!!! 20-30L of PH 6.5 water
6 PH is a little low for soil 6.3 to 6.9 PH would be better
I go 6.6PH

dont flower just yet, fix nut porb first, flush , weight 2 days, flush agan until run off water is same PH as water put in, then light nute feed with veg nutes,weigth 2 days, then flower
you might wont to get EC pen

ok I went ahead and flushed. Leaves immediately drooped. So I just wait about a week for the soil to dry and continue as I was only this time with less nute dosage?

that is some great advice. thank you very much.

some pics of the recovery... thanks again!