Late flowering, DWC in trouble.. pics

So my plants keep getting worse and worse and i cant seem to get my checks and balances straight. I am pretty sure this is a combination of heat stress and PH fluctuation. My PPMs havent been higher than 1000 and havent seen nute burn (that i know of) but the leaves seem to just be drying out starting at the top. (i think)

I have used GH Flora with cal mag and hygrozyme throughout, with 2 300w cfls and other cfls scatterd around the plant. Temps never got above 80 but the lights were pretty close to the plants. And i have had fans blowing fresh air into the room and on the lights best i could.

I changed res tonight planning on beginning to flush and only have PH water in there right now. However I can only seem to find about 5% amber trichomes. I thought whatever if its not quite getting better im going to be harvesting soon anyway and will do it better next time around. But now im having second guesses.. Should i just flush and harvest? Or try to get this problem solved and let them go longer..

I honestly have no idea how old the plants are and how long they have been flowering, but i would say at least 9 or 10 weeks..

First pic is from a couple weeks ago when the problem wasnt nearly as bad.. rest are from tonight.

They look pretty smoked. High nutrient will cause deep dark leaves. Flush for a week and harvest and chalk up to experience. Next one keep track of days, pH needs to be stable, lights are CFL so fine right up next to plants, introduce your plants to nutes on a gradual increase keeping an eye on color to let you know whether they are being fed too much or not enough. Depending on your plant rather than what it should or shouldnt be according to the book.

Im no expert but they look over fertilized i grow DWC and have found depending on strain and light intensity (higher watt HID) that i have to go below the recommended nute dose seems DWC builds up toxicty quick ive used as little as 25 % strength and got monsters out of em. I usually start out weak and read the leave color to see if i need an increase it is easy for me to tend to over feed em.

i wouldnt even flush for long maybe 24 hours... i doubt it would matter are they even drinking still ? check if there not drinking harvest now. it looks like a mixture of to much ferts and maybe your ph being off.. but im no pro

how often were u changing out the res with fresh water ?