MR2 is a high quality fertilizer from Metrop. This nutrient is for bloom phase and is used from week 4 in bloom to 1 week before harvest, during the last week you should only water the plants with clean water.
MR2 can be used in all mediums like soil, coco and hydro.
Note. These nutrients are highly concentrated so be sure to follow the nutrition chart very carefully and do not overdose.