leaf curl - causes?

so i have 5 autos at one month and two are almost not growing at all

the two im having problems with are my diesel and my quick one. They are both about the same size, maybe 6 inches high,both suffering from extreme leaf yellowing in the bgger older bottom leaves and major leaf curl in the smaller newer ones. Both have 6 to 8 bud sites but both look really weak.

one month old autos
soil is biobizz allmix
nutes gh floragrow at strength
lights are all cfl 5500k and 2700k combined 500 watts
schedule is 20/4
watering every three days or so

thanks for looking and help

Whats your Ph? Also take note of the burnt tips and curling under looks like nute burn unless your ph is off causing a lockout

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yeah,......dont have a ph meter yet......thats my bad.


let me ask you this thouh.......if the other 3 autos are doing fine but these 2 arwnt even tho they are all getting the same treatment can it still he nute burn or locout or ph?