i have covered this b4 but 1 more time i suppose
i too used to ph down my water to 5.8-6.0 which would result in a crash around week 5-6 that looked like an nitrogen problem then i found out that soilless mixes like coco and rockwool have a naturally nuetral ph of 7 and need to be ph controled whereas peat has a natural ph of about 5 so its too low to begin with, but the lime will act as a natural buffer which makes moore into a soil mix considering most soil mixes are 50% peat anyhow give or take

you want to treat #4 like soil
hers some pics at about week 4 flower