If you jump on there site they have a dosing guide.
If low light plants half rates of chart will be ok if med high light plants dose as charted.
You need to know what plant problems and soluctions by looking closly at your plants.
Here below is some problems with soluctions.
Element Leaves to first
show deficiency Symptom
Nitrogen Old Leaves turn yellowish
Older leaves die off quickly in extreme deficiencies.
Iron New Leaves grow in pale or yellow
Greenish nerves enclosing yellow leaf tissue
First seen in fast growing plants
Potassium Old Pinholes appear in older leaves, and slowly enlarge
Yellow areas
Withering of leaf edges and tips
Calcium New Distorted leaf growth
cupped leaves
twisted and bent leaves
twisted and short roots
Damage and die off of growing points
Yellowish leaf edges
I have seen an extreme Calcium deficiency which resulted in a sword plant where new leaves were growing in almost completely white.
Magnesium Old Yellow spots
Often appears similar to iron deficiency since mg deficiency prevents a plant from properly using iron.
Yellowing of old leaves starting from edges while major veins remain green
Boron New Dead shoot tips, new side shoots also die
Brittle stems
Similar to calcium
Sulfur New Similar to nitrogen deficiency
Manganese New Dead yellowish tissue between leaf nerves
Copper New Dead leaf tips and withered edges
Zinc Old Yellowish areas between nerves, Starting at leaf tip and edges
Molybdenum Old Yellow spots between leaf nerves, then brownish areas along edges.
Inhibited flowering
Phosphorus Old Stunted growth.
Sometimes leaves become darker green
Also symptoms can be similar to nitrogen deficiency
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