when i started using bio /bloom , grow ect , it took me a while to work out whats best, but i start at 3ml for 2 litres then every week i go up 1 ml until week 4 (6ml /grow. 6ml bloom, 5ml top max) after wk 4 i start going down 1ml per week until i flush at week 8 (then 2 weeks flushing or until finished whatever comes quicker) any hoo thats what i do , but you may want to do it different.. good luck pal