help plz!!!!!!!!

i woke up today and my plants have got brown spots on the leaves and have gone a pale green colour. i would provide pics but i am onli using a phone camera and you cannot see the detail because they r only small. any ideas of what they can be?? i read on the FAQ it could be light stress but i am not sure.

it could be lots of things.

What have you done recently thats different, is it a new occuring problem?

i havnt done nothing different except instead of leaveing it 3days before watering i left it 5..

Is it a different source of water to before, has it been prepared differently

is the plant closer to the light than it was before?

the water is the same, the plant is closer to the light now because i have not moved the light for about 2 week because i dont want them stretching, i think it coukd be light stress i have put the lights on 18/6 now.