Sudden Yellowing During Flower. Help!

[SDJ99]

Hi! Super lemon haze in week 5-6 of flower. Yesterday, the girls were thirsty so I watered them with distilled water as I thought I gave them too many nutes last week. Today, they were insanely yellow. Please help!

 

[Pondracer]

Personally I don't ever water with just DI, though I use it exclusively to mix for normal fertigation. If my plants looked thirsty then I would just do an extra fertigation event.

 

[SDJ99]

Advice please?