what the hell am i supposed to do now???

So i was trying to avoid posting in here but its been over 2 weeks i have no choice.

Problem: curling, burnt. and the main issue is shes been stunted for over 2 weeks.

i had an issue with 75% strength botincare pro grow about 2.5 weeks ago
i cut down to 25% strength and started a maintence week.
all of my girls except one(who is a different strain) have signs of being burnt.
problem is theyve all forgiven me and continued to grow. quite rapidly actually.

my problem child is only 7 inches tall and the other girls range from 11 to 13.5 as ive fimmed recently.

i do feel she is growing outward tho her undergrowth slowly has grown.

i stopped feeding her now. i seperetly water her with airstone filtered tap water.

ph 7.3
roots organic soil
botanicare pro grow
600w 20in away
c02 enrichment

temp: day-77
night-60

humidity ranges from 40-60.

constant intake
2 circulatory fans.

The beginning of nutrient burn. Probably a pH/PPM issue at this point. Flush well with water and start over as far as nutrients.

ive already done that.

i flushed. cut down to 25% flushed again and last 2 waterings no nutrients. still no change.

Old growth will never heal, keep an eye on new growth and get your ph down to mid 6s.

The new growth actually looks pretty green, when doing seeds sometimes you just get runts. Kind of an aside question, but you said "constant intake" (air exchange?) but if youre doing co2, shouldnt it be a closed environment with higher temps,,like mid 80s? Other than that, I would just get the ph down like the other guy said, and resume feeding

bustin, yes you are correct co2 enrichment requires a much higher temp of mid to low 90s but co2 needs to be monitored closely around 1200ppm it can be fatal to plants if not done properly, and co2 enrichment is not beneficial if you have any problems like ph. when you have a perfect environment co2 is can make a huge difference but everything has to be 110% perfect with NO flaws!

If you've flushed recently then just get the pH down to 6.5-6.6. Water with mild nutrients.