DWC Wedding-Gelato, Whitewidow

Begin of week 3 and barely any growth last week. Some signs of problems showing - purple leaves, stunted growth, droopy leaves, brown spots. EC has been 0.8 since week 1 - no new nutrients added. EC probably too high for plants of this age. They have had to deal with stress from humidity and temperature dropping a bit low while I 'tuned' the grow tent conditions (18C and 35%!) Biggest problem has probably been over watering. EC has been 0.8. Day 5 in the week I changed the resevoir and gave them only water for a day before adding nutes. This was because I was told they had nutrient burn but day 8 and they still look fucked. In the last day of the week I fucked up. I diagnosed what I thought was calcium deficiency so gave the plants 5ml of vitalink calmag. I did not check pH after (the nutes I have used so far have not altered pH much) but found the plants the next morning looking much worse and the pH was 6.5. Hopefully this week the plants can have some stress free growth and recovery.