TIPS: Best is to use potassium together with iron, to exclude deficiency's and to be sure both elements are present.
In case of heavy planted aquariums or in areas with soft water: Use weekly Potassium. Normal dosage is 10 ml per 100 litres and raises the concentration of potassium with 4 mg/l.
Good product overall by Easylife
Excellent product & using this twice per week for my planted tank. Genuine product & at best price from IndieFur.