plants got me worried

The last two days I have been noticing my plants are looking unhealthy and now little light green turning to yellow spots are forming at the edges of the larger fan leaves and a few younger leaves are looking half formed and curling.

I feel the need to flush the ladies but am not sure on when to add the new nutrients and what will happen to the PH if I flush. My understanding is that the PH will be corrected to what ever my soil was before adding nuts. I can then begin proper water, and ph monitoring to attempt to fix the issue before i get too far into flowering.

I would like to move them into flowering in the next week or so. Can I do this or no?

48" flor daylight 6500K x 6 (four top two side)
4 white widow
5 gal pots with soil
ph- all pots 7.5
watered yesterday 1/4 strength Miracle grow all purpose
temp reading between 76*-83*
Humidity 40%-55% (depending on watering)

Those look good.. don't see a problem??

If your worried about ph becoming a problem then you can top dress with some dolomite lime.. It will keep your ph stable around 6.5

and if your reading runoff for the ph then that's really inaccurate..

unfortunately its just a probe meter and I am measuring soil. the odd spotting and curling of the leaves are not an early sign of nut burn or lock out? will flushing achieve anything? will flushing hurt anything? how long after flushing should replacement nuts be added and in what strength? will adjusting water PH be enough to achieve a lower soil PH?