What's wrong with my plants please? (pictures attached)

Hi guys,

So this is my first grow i started 4 weeks ago, indoor in a growbox tent. Plants are now ending their 3rd week of vegetation stage.

My growbox & other specifications:

- size: 240x120x200 cm (8x4x7 feet)
- vents: intake 280 m³/h , out 355 m³/h.
- lamps: 2 x 600 W HPS, I keep them 60cm away (2 feet) from the top of plants.
- soil: Biobizz light mix
- fertilizer: Biobizz starter pack (Bio-Grow, Bio-Heaven, Bio-Bloom, Root-Joice & Top-Max)
- plant type: Sativa Sacitrus-Haze feminized
- pots size: 30 Liter (8 Gallons)
- watering with rainwater from the well (pH about 7-8 but i lower it with lemon juice)
- Temperature & humidity: lightsON: about 30-31 degree Celsius (86-88 F) , lightsOFF: 20 C (68 F) , I know my temperature is a bit high with lights on but cannot do anything to lower it at the moment because it's warm outside. The only thing i can do one day is to install AC in that room maybe. Because these HPS lights 600 w are making so much heat in the tent.

There are 8 plants in the tent. One is a bit smaller then others because I made a mistake when transplanted them I accidentally broke some of its roots. So it was in a shock for some time until it started to recovering.

The problem is that their bottom leaves started to get some yellowish spots on them, like you can see in the attached "leaf" picture, and looks like drying out. I ripped of these unhealthy leaves from them.

What do you think may be a cause of this?

I made a mistake with fertilizing in their 2nd week because i misunderstood instructions and thought I need to give instructed measurements per one plant, so I have mixed all of these fertilized liquids in a glass of half water then gave half of this mixture to each plant. Later I have found out that these measurements needs to be diluted in 1 Liter of water, not in a half glass of water like i did.
Can this be a reason of this? Maybe I burned their roots too much...

In overall what's your opinion about this grow and do you think my plants are in danger of dying because of these leaves?

Pictures are made while the plants are sleeping, with a phone's flashlight on.

Thank you so much in advance!
Wish you a great weekend.

Honestly they don’t look to bad to me.
Yes you may see some minor issues since you gave them a hot shot of food. Just water when needed and skip the food for a little bit. I don’t know much about the soil mix your using but if it’s a decent soil mix it should have enough food to carry them for awhile without feeding. If it’s a soilless mix then you will need to feed every watering. Your ph is good and I wouldn’t adjust it if it’s a soil mix because the soil buffers on its own and without testing the PH after you add the lemon juice then your just guessing on PH value.

I don’t see any major issue that would make me start trying anything drastic at this time. Just try to get a handle on your feeding and watering habits and keep it simple is best.

I don't see any major issues. You should keep up with weekly preventative maintainace. If you are an organic grower, you may try 100% all natural, all-in-one Eliminator insecticide & fungicide at https://doctorzymes.com/wizard. It will narually prevent and eliminate harmful insects, fungus, mold, mildew, viruses, and bad bacteria causing disease in your organic garden without use of harmful chemicals, clogging oils, killer pesticides, residue soaps, and other unnatural ingredients.

Since they are the size they are, and that’s all you see wrong, I wouldn’t worry. They look good. Keep up with your feed, and know they may ask for more per feed soon if not already. Like I said they look good, and I’d just keep doing what you’re doing.