HELP! I need help/guidance on a situation regarding ppm and toxicity.

[msi]

Hey so I am currently growing a strain from mephisto genetics and this plant has been a pain in my rear for so long, she is extremely sensitive to nitrogen and I am growing in a DWC 5 gal bucket and only filling about 3 gallons of water.

That being said, my plant is in its 3rd week of flower and at this stage I have to use such little amounts of anything that has nitrogen in is such as calmag, flora micro and gro that even after adding a bunch of bloom and koolbloom, my ppm still ended up below 500.

I am not sure what to do in this situation, do I just up the bloom nutrients by a lot and pretty much go through a whole bottle of koolbloom to make up for the lack of ppm from other nitrogen filled products lol?

If anyone has any good advice I would love to hear it, thanks.

[SirSmksAlot]

Some plants are just light feeders. Are you seeing any signs of deficiencies?

[msi]

Some plants are just light feeders. Are you seeing any signs of deficiencies?

To be honest I am not sure if I am dealing with potassium def or light stress.

Tips of all the leaves have turned yellow and the top canopy has some tips that are curled upwards with yellow tips that look to have stayed yellow or turned brown. my quantum board is 24 inches away from the top canopy and it's not even at 100% wattage (240w) its at 50-55 as I await for my hole saw to arrive so I can put together my chiller and setup a rdwc system for the plant before raising wattage which in return raises temp but I won't have to worry much due to the chiller being active at that point.