Can someone help ID what is wrong with this plant?

[Icefisher]

Hello all, am sort of desperate, I do not want to lose this plant if at all possible.

I am using Morgan county Master blend fertilizer, Calcium nitrate, and Epsom salt.

The ph of my nutrients is 6.0 with ppm of 810 and correlating EC of 1.21. I am using a 1000 watt HPS bulb for about 15 hours a day. The plant has exhibited these symptoms for some time now and every attempt I have made to improve the situation have not worked. I have changed the solution out almost every other day. I even tried soaking the plant in buffered water for a period of time to see if that would help. I do not understand what could be wrong, the plant is still putting out new growth and the root system is white and healthy looking. It even has several blossom sets on the main stem. I have attached a couple of photos. One leaf gets it and then others on the same branch get it curl and dry up. Then the whole branch dies off. I have been trimming the diseased branches hoping that the plant would mend itself. Please, does anyone know what it could be? Can it be saved?

Thanks Icefisher