Last water change I made I set ppm at 700 and after 2 days I added 2 ltrs of water ppm and after another 2 days I added 5 ltrs of water . Ppm drops a little like 200 but after one day it goes up again . pH was stable but now it keeps going down again . And I keep adding pH up to keep it stable as possible
It does sound like your going to get Hermes if they are flowering on veg light cycle( unless autos ? )
For heat therw are products to help cope with higher temps. I use one called liquid ice but airflow has to be in and out . If in buckets try using frozen bottles to bring res temp down asap. Any damaged leaves need stripping to avoid rot and wasted Energy too i think. There are good products for stress too that may be worth a look. Have used A.n revive and also used superthrive in the past that I feel did help.