Leaves are not okay.. suggestions

Hello everybody, first time grower here and trying my luck with a single plant, that will hopefully turn out female, but before that I have to make sure it survives that long and recently I've had issues with my plant. As you can see in the pictures, some top leaves are turning crispy brown and are dying. I'm not sure what's causing this, either the lighting (2 20 watt cfl bulbs) or if I maybe used too much nutrients. Any suggestions are greatly appreciated, thank you.

definitely looks like nutrient burn. Get some RO water (tap will work but always use purified when possible) pH it to 5.5-6.0 and only use this to water the plants. Wait until the dirt feels dry before watering again, don't just keep watering to flush it. Cannabis is a very resilient plant, just cut back on the nutrients and you should see improvements within a week or so. Note that damaged (burned) leaves will not recover. Look at the health of the new growth to see if your problems seems to be going away. After you see the plant improving in health, start to add nutrients half strength, wait a week, then if all looks okay go back to full strength (less than you were before obviously) Good luck!

Thanks for responding, I'll start using water only and keep it to the pH level you have described. No nutrients until they seem to start getting better, thanks for your help!

no problem! you can also trim off damaged leaves using the pinch method or with a sterilized razor blade. Try not to cut off all damaged leaves at one time to reduce the stress this may cause the plant. Leave the ones that aren't too bad, just take off really bad ones. Grow on!