please help me diagnose?

deep water culture(5gal buckets)
ph 5.6
ppm 1000(10ml pbp grow,5ml Lk per gal-20 gals)
tap water ppm 324
air cooled light 400w
clones are still in veg

Jim, feeding with every water is generally a big no-no. I would venture to say that over fert of N, K and Mg has caused a Ca lockout. I would stop feeding with every watering and back those ppm's down-your tap water also appears to be 'hard'. try using distilled water with backing off the ppms and see if it doesnt clear up

check out this thread:
http://www.icmag.com/ic/showthread.php?t=11688