get them back on nutes right away!!! 5.8 ph is perfect as stated earlier. coco/perlite mixes are straight hydro and have no inherant nutes. be sure to feed them with every watering. depending on the exactitudes of your medium you may have to water more than once per day to keep the moisture level just right.

also you say that your 600 watt light is 5 ft away? as in 60 inches? if we are talkiing about an HPMH or HPS that has to be so much closer!!! With your plant taking in these nutes it will need the light to process them otherwise your plant will suffer.

I have 4 600 watt HPS bulbs and my canopy sits about 8 to 10 inches away.

hope this all helps.