need help/advice desperately

What's up everyone, I normally just cruise thru here once in a while for research and when I'm bored, but now I call upon it for some advice. My ladies have taken a turn for the worse the past 3 months and I have no idea why. Normally my gals finish nice and green and strong and as of late as you can see in pics below they have not. It has started to spread into veg as well. I pull perpetual every 2 weeks so in the pics there is weeks 3, 5, and 7 as well as a snap of next 6 going in from veg. Also the snap of leaf is one from veg. As you'll notice its a pale green with brown spots forming from middle out, progressively getting worse as the weeks go on particularly in flower. By week 3 the problem becomes more apparent, by week 5 majority of leaves are yellow with brown spots on some leaves, a lot of brittle, crispy leaves and by week 7 it has taken over the plant. It is starting to affect my yields in flower and growth rate in veg now yet nothing has changed from what I have always done for 6 years. I run pro mix HP with advanced connoisseur A&B, piranha, tarantula, voodoo, big bud, sensizyme, bud ignitor, nirvana, B52, and overdrive. I water Twice a week ( feed/water) start off at 1000ppm week 1 and work up 100ppm a week up to week 5 capping off at 1450ppm and working down from there until flush. My water is all RO and always ph'd to 5.8-6.0, I just replaced my filters in RO last month thinking perhaps water wasn't filtering properly therefore throwing the pH perfect off in the advanced which would create a lock-out however I haven't seen any difference for the better since replacing them. I also thought they possibly getting root bound so I repotted 6 into bigger pots which are the ones pictured below currently in week 3 and still showing same signs of deficiency. My rooms always at 85°f day 70° night and ppm's at 1600 ran by a cap co2 8 burner. Again guys I haven't changed anything ive always done and yet have seen a 30-40% loss in my yields as compared to before. Any help and advice is very much appreciated, I swear man I'll pay it forward if someone can crack this code for me lol

did this start in the winter months? have you eliminated this being a pest problem? looked closely at your medium and your run-off for critters? closely examined your plants for bugs, especially the back of the leaves?

Thank you kindly for your timely response, I have and I always keep a close eye for bugs. However, I have not thought to inspect the soil and runoff as I have only ever had mites in terms of a pest problem and didn't think of that to be quite honest. Anything you can suggest to look for in particular in soil/runoff?

use a magnifying glass. look for something that doesn't belong, larvae. you'll know it when you see it. you may even see movement in your medium. look at the same place for a bit, you may see something move. stir it up a bit, and keep your eyes open. doesn't seem right that you've changed nothing, yet you have change...

Much appreciated man, I did notice a slight discoloration on roots last time I harvested was a brown purplish red color it wasn't dominant but the tinge was there but I will certainly check runoff as you've mentioned....super aggravating man can't figure it out and I'm sure its something stupid

I flush my babes one time per month and I hate it, they love it...and the monthly spray with neem oil, just to avoid strange things like bugs showing ypp ....lol

to my blog: https://www.rollitup.org/blogs/blog32238-neem-oil.html

Haha not a bad idea man I can stand to foliar some neem once a month to avoid these situations I suppose...

Are you sure your ph meter is calibrated properly?

I don't work with those nute brands but you may need to adjust ratios.

Normally I always check my nute mix before I water just to make sure pH perfect is working with the advanced which it does as long RO is filtering properly and my ppms are in order. I check my meters in 4/7 pH solution and calibrate accordingly weekly and more so since this problem started occurring, as I too thought this was the issue. Thanks for your input though

I checked out soil and leaves and seen no signs of pest or bugs in soil. Roots/soil looked good and healthy so I'm prob gonna rule out pest issue

I'm wondering if this is a cal mag issue? Shouldn't be with advanced based upon the claims you don't need to supplement cal/mag when running the two part with RO which i am, any thoughts?