Hello mowax thought I would share some of my research in an aim to prevent other growers from having the same problems I've had.
What the Cannabis community commonly thinks of as nutrient burn, pH issue, or deficiency is actually the result of Chlorine and Chloramine in Cannabis. Chlorine and Chloramine problems will present themselves in multiple ways. The symptoms are burnt leaf tips (reddish brown tinge about 1-4mm in length that point up), rusted spots, naturally torn leaves that shrivel where broken, and a reddish brown micro spots on your leaves. You may also experience narrower fan leaves. When in flower, buds take 2-3 weeks longer to hit their stride and will never hit their full potential. You wont get massive buds if your plant has been in contact with to much Chlorine and Chloramine.
Chlorine, is only a micronutrient and your plant requires it in only very small quantities. If using tap water, you'll hear commonly that you need to bubble off your water for the chlorine to evaporate because it can kill the good bacteria in the water. This problem is only the tip of the iceberg. Chloramine is said to do the same thing but it cannot be bubbled off, and both (especially Chloramine) causes a wide range of other problems.
Now the real kicker is what is actually going on inside the plant. Chloramine and Chlorine were studied in an article titled "Redox agents regulate ion channel activity in vacuoles from higher plant cells," the author tells us that Chloramine irreversibly damages flowering plants vacuoles resulting in the inability for the exposed channel to transport ions. A good quote from the articles abstract "The regulation of channel activation by glutathione may correlate ion transport with other crucial mechanisms that in plants control turgor regulation, response to oxidative stresses, detoxification and resistance to heavy metals." Further reading will tell you that Chloramine is directly responsible for a wide range of internal problems.
I'm no chemist or horticultural, but this clearly tells me that flowering plants are significantly inhibited from reaching their potential when exposed to Chloramine. Do yourself a favor and use only the best quality of water for your plant by using a filtration device to remove Chlorine and Chloramine.