I've had the same prob in the past. Found epsom salt when watering (each time, but then I water once a week) prevented this (didn't really stop it once it started)
Its a guess dude, you could have bugs in your soil, ive looked at your pics and read through all your info, am stumped just like you, i like you also do hydro and soil, i buy the same soil all the time but you can get the odd prob, we truly dont know whats in it, soil does carry bugs and eggs etc, the glory with hydro as you know is if it all goes to plan you get mint results, but if you fuck up, you fuck them all up, but going by your pics dude i just dont know what they are not liking. you have looked at them in detail for bugs ?
Best of luck, i worry aswell, but it always works out in the end, have you ever though about ''CHURCH'' you can pour diesel on those fuckers and they still grow lol.yeah i guess i could do this..worth a shot...ill have to wait they are sleeping now and for the next 3 hours
man its a tough one, and harder to solve as i cant see them, i know you have put up snaps etc, but you know what i mean, am feeling your pain man, i just dont know, i,ve went through the net and showed them to fellow grower friends, sometimes the best thing to do is ''nothing'' the more you fuss the bigger the problem becomes, if it was me dude, id be going for pure h2o, i live in scotland and we are blessed with good water, i have never looked at my ph in my life, just no need, leaves do say it all, its their faces, and you no a happy face=leaves, ill follow your report dude and say a prayer.ok so heres the deal..its still continuing to affect more leaves..cal/mag obviuosly didnt work..i put potatoes down on the soil to see if some larve would attach to it..so..im thinking no bugs..my ph was 6.9 it raised a bit to 7.5 im assuming because of the calsium so i put some sulfur 1tsp on the top of the soil to lower it back down..dont know what else to do eh