DWC Plants seem to be becoming sick

[Blizzin]

The spots could be a K (potassium) deficiency. Eventually the rest of them will show signs, like dark green leaves, then they lose luster, leaf margins turn yellow, progressing to rusty or brown spots then they die.

I would flush the system, use a mild solution (600)for a week and make sure you ph. :thumbsup:

I am Phing like every 6 hours never leaves 5.8 to 6.0. Also about flushing it I just put a new batch in there last night after seeing the spots and droping think I should still cut back to about 600ppm? thanks for help