i have no idea what is going on with 1 plant

[thermoUncle]

Really im trying do something with this plant, and i really dont know where is problem :>
all plants got same nutrients same water

im using only biobizz

her sister flowering like crazy tops are bigger 4 x

sick blue mystic, she looks same from 5 days ? flowering is stopped
day 40

and her sister

please help me

 

[NuttyProfessor]

looks like a start of nute burn , hows your ph ,

 

[thermoUncle]

i dont have ph tester(im out of money now..) everything happened after flo nutrients but i put only 0.5 ml top max 0.5 biobloom, 1 ml biogrow, 1 ml bioheaven, then i gave her only water, and again i lower nutrients to 0.3 biobloom 0.3 top max 0.7 heaven without biogrow then again only water and yesterday same 0.3 biobloom 0.3 top max 0.7 heaven

her sister and 2 x northern lights auto got much more nutrients (about 100-110%)

and one more thing blue mystic with yellow leaves is anyway the tallest.. but flowering is stopped
aaa.. one more bottom leaves are ok

First Grow - Indoor - CFL - 2x Blue Mystic Auto 2 x Northern Lights Auto Nirvana

 

[Quagga]

Btw, what kind of light You are using?

 

[22naru]

looks like a start of nute burn , hows your ph ,

+1
try to get a ph tester. gl