Nute burn, deficiency or something else?

Hi guys,

My Light of Jah is having problems. It grows fresh leaves, but all the big leaves wilts from the edges and dies, both top and bottom. Half the plant is dead. Here's what I have:

- Light of Jah, 3 feet tall
- DWC, 3 gal.
- 120 w LED
- pH at 5.8
- 5 ppm water with MaxiGro (250 ppm)
- 68 F air temp, 65 F water temp

I used MaxiBloom for a while, but it looked like it got N deficiency. I know the ppm is low, but it doesn't go down at all. Seems like the plant isn't using the nutes at all.

I've used the calibration liquid to make sure the ppm-meter and pH-meter aren't broken, so it's not that. Is there anyone out there who can help?

Read that MaxiBloom is very close to the Lucas formula, but a little short on N. I added 10% MaxiGro now and keeping it at 258 ppm for now. If the ppm doesn't start dropping, I won't add any more nutrients for a while. How fast should a healthy 3 foot plant in a 3 gal bucket go through that? It should go pretty fast, right?

The PPM is now dropping about 10 points a day. It's at 230 now. Is this a slow drop? I should add some more nutes, but not much, I would assume? Maybe up to 300?