Leaves not looking healthy

It seems a bit more like a deficiency issue to me as opposed to a toxicity issue. If your ph is right, and your using coco as you say, it’s probably lock out due to high ppm in your soil. It could need a flush to cleanse the salt build up and allow the plant to take up nutrients.

sorry for not giving enough info, i am growing in coco, using mars hydro ts3000 with almost 12 inches away from light, humidity at 40% and temp is around 24 celsius

Good morning, So are you growing in soil? If so you would want to raise your ph more to a 6.2-6.6 range... if it's coco you still may want to get closer to 6.2 With your edges changing the way they are it sort of rules out a nutrient burn which would just hit the tips. When i zoom on the plants it looks like mainly the top has this..the bottom leaves don't seem to have this whole edge discoloration. Maybe change the ph slightly, but also check the distance of the lights to rule out light burn, and double check your nutrients are being fed at healthy doses. Happy flowering. ✌️

Without more info its hard to say for sure...….what kind of light, and how far away is it? What are you using for nutrients and how much are you giving and how often. Whats the temp and humidity in the room?

If you're in soil, then your pH is probably a little too low. When this happens, your plant will have a tough time taking up some nutrients. I would readjust to 6 - 6.2. This could solve all of your problems. Also it looks like your fan might be hitting the plants directly, this can be an issue.