Hi AmsterdamBase, 28° might be a bit much.
From your diary its not clear what you are using as nutrient. You mention Plagron but in week 6 you also say "since i haven't added any nutrients".
Plagron's nutrient should be added every time you water the plant, there will be no benefit to not use it everytime.
If you dont add any nutrient then you should, if you are using Plagron's nutrient you should really stick to the nutrient's schedule.
Hope it gets better man, your plants have a good potential !