To much light or is my plant sick?

The end of the leafs of my plant are getting yellow and dry. i think its because its to much light but the light int really that close to it.

i moved the lamp to the right because I a scared that the smaller one wont get enough light.

Also my plant got yellow dots and the smaller one even a whole yellow leaf.

I think I vertilized to much but im not sure. I wont do it the next few weeks. But also a few leafs at the bottom are very dry and are breaking when you touch them. Is it the fan?

Humidity is around 60 now bt they grew in a room with humidity about 80 percent for a month or so. I dont know the ph because I dont have a ph pen but i not sure if thats the problem.

Some infos:

-strain is Afghan Kush

-its on the 3 day of flowering

-It is pre vertilized soil

-the light is a Marrs Hydro 1000

-the temperature is about 19-20 degees

-Its an 70cmx70cmx160cm grow tent