Rockwool ph issues drain to waste

  • Thread starter 5farmers
  • Start date
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Looking for some advice here:
Grow details....
Current culture nutrients
1200 plants
50 lights (Luxx HPS 1000w)
room temp day 77f night 70f
day humidity in veg 70% night 60%
flower day 60% night 55%
drain to waist.
feeding 100mL shots 2-3 times per day in first week, increasing to 6 to 8 times 100-150mL in week 8 of flower
water at 5.5ph
Veg 800-1200ppm co2
flower 1200 co2 until week 7 decrease to 450
heres my issue(s)

its hard to SOAK 1200 cubes underwater....
so I use 2000 gallons and wet the crap out of them with 5.5 ph nutrients before transplant at about 500ppm
i can’t get the cubes to inoculate....

I maintain a reservoir ph of 5.4-5.6

i flush the lines by circulating back to the tank for 30 minutes up to the second each watering cycle begins so that the ph in the lines when feeding begins is always 5.5

seems like it would work? However; if I stab a ph pen in the bottom of the cube it’s anywhere from 7.2-8.2.... every single cube.

I’m using florashields so very very minimal algae growth on cubes.

runoff from cubes always 7.5-8.2.... why????

drain to waste.... never recirculating through the cubes.

any thoughts would be greatly appreciate.

theres no big signs of neglect in the plants... but I feel like their not at 100%because some of the nutrients can’t be absorbed when the ph is that high in the growing media??

photos attached are day 8 of veg
and week 7 nloom


Is it just the cube at 8? Or the runoff itself?

The plants looks amazing. I'm thinking you are getting a reading of the cube not the nutrient
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