Brown dry spots on older fan leaves

[TopShelfCBD]

Have a bunch of dry spots on some fan leaves, new growth is unaffected at this point

This is only one plant out of four, the Jack Herer Auto

RDWC, PH IS 6.04, PPM is about 900, water temp is 18 degrees Celsius

Tent temp is 22 degrees Celsius, and RH is about 30%

4 weeks into Veg

New growth

 

[TopShelfCBD]

Anyone have any ideas?

 

[PagodaVapors]

Brown, dry spots on older fan leaves

Have a bunch of dry spots on some fan leaves, new growth is unaffected at this point

This is only one plant out of four, the Jack Herer Auto

RDWC, PH IS 6.04, PPM is about 900, water temp is 18 degrees Celsius

Tent temp is 22 degrees Celsius, and RH is about 30%

4 weeks into Veg

New growth

900 ppms is way too much for a 28 day old
Plant. Or how old is the plant ? Did you have 2 weeks seedling then started counting 4 weeks veg. 6 weeks total 42 days old? Even so 900 ppm is quite a bit much for her. What nutrients are you using and what's your mixture ? How much ml per gallon