Iam using tap water ahd jacks 321 as a base. So ill probably stick to 2grams of iron for 35 gallons of water.
Probably do this
Week 5- 20 grams mpk, 1gram iron / 35gallon water.
Week 7- 45 grams mpk 1.5 grams iron
Week 8 - 45 grams mpk
Week 9 - 45 grams mpk, 2 grams iron
Week 10- 45 grams mpk
I slowly cut out my other nutes as i come up to week 10. Then do a major flush then run just water for a week with 8 hours light. After that point they seem pretty flushed as coco doesent like to hold onto these nutrients long. I try to go for that nitrogen lacking faded look.