Rockwool Leaf Edge Curling (DTW)

Hey guys,

Long time RDWC grower here who wanted to give rockwool DTW a test run.
I'm having some leaf edge curling (pictures attached) and I'm not sure what's happening.

Vitals:

• Grow Medium
  • Big Momma 8" Rockwool cubes
  • Initialized @ pH 5.5 for several hours
• Nutrient solution
  • GH flora gro/micro/bloom @ 1:1:1 ratio
  • pH 5.8
  • temp 60° F
  • RO source water (not using Cal/mag supplements right now)
• Feeding
  • Hydro Halo drip rings
  • Pumped from premixed nute res (not aerated)
  • Top-drip ~1min / day until there is a pint or so of runoff.
  • Each plant is getting ~0.5gal nute solution per feeding
  • rockwool cubes are never allowed dry and always seem moist to touch
  • Runoff pH ~6.0
• Lighting
  • 600W HPS
  • 32" above canopy (since they are still young)
  • 24x7 during veg
  • I tried shading them for a few days so the light was not as intense, but did not seem to help.
• Environment
  • 4x4 grow tent
  • Air Temp ~80° F
  • RH ~30%
  • Air replaced every few minutes
• Genetics
  • Jack Frost
  • Cloned by me from previous generation
• Observations
  • slight purple-ing in some stems
    
  • slight yellowing / somewhat spotty discoloration in older leafs
    
  • leaf edges are curling in both new and old growth
  • several gallon flush with ~200ppm solution did not seem to help
  • No burnt tips, so nute overload is not suspected
  • rockwoll cubes are not sitting in standing water
  • Generally slow growth, not feeling healthy
  • Leafs feel a bit 'dry' to the touch on the edges

I am stumped. My only guess at this point is that I am significantly underfeeding since I am limited to the size of my 12" plant saucers (at least until I create a better DTW drainage setup).

I've read all sorts of different feeding schedules. Some on these boards are feeding multiple times per day for multiple minutes. This seems like a a HUGE waste to me and I fear I would be drowning my plants. They don't seem capable of consuming what I am providing already.

Any insight or suggestions would be appreciated.

Thanks!

[LIST said:

[*]Lighting

• 600W HPS
• 32" above canopy (since they are still young)
• 24x7 during veg

[/LIST]

Thanks!

Click to expand...

I Think plants need sleep why not try 18 / 6

@Terry385 thanks, yeah I'll give it a try. However, I've done this same 24x7 veg on every one of my previous grows (and just recently with same strain) without any issue. Feels more like an under/over feeding issue?

I'm having trouble finding a definitive answer to feeding frequency and volume when it comes to DTW/rockwool. It seems to be all over the place in other threads..