Start with three things: your growing medium, source water and plant stage. For soil and suitable hydro systems, choose the Ferro Soil/Hydro A&B range. For coco, choose the Coco range. Growth and Bloom are separate base feeds, so match the version to the stage.
Using reverse osmosis water? Choose the corresponding Osmosis A&B range for soil/hydro or coco. Measure your water first. The description “soft water” alone does not explain its mineral composition. Do not automatically add extra calcium and magnesium to a complete osmosis feed.
Our advice: select your base feed first. Then check whether the schedule calls for a root stimulator, enzyme product or bloom supplement. A larger container does not change what the formula is designed for.