Too much or too little water for marijuana

I do want to add, the damage on the leaves looks like it is due to a pH problem or “nute” burn or maybe both. Not over or under watering. Although over watering for a long time can contribute to pH problems.

how can u tell the diff. between over watering & nitrogen toxicity.
my fan leaves look dark green and heavy. my soil always feel too cool to me, inspite temp. read 75-80
400wattmh 12in away cool light

Over-watering the leave are green and usually look healthy but are drooping down. Can lead to root death and susceptable to disease.

Nitrogen toxicity looks a lot different. the leaves are pale green to light yellow and just look sick.

Look in the Guides section at the top of the page under “Symptoms Checker”. There are good pictures there to help identify the problem.