An arrhythmia is any disorder of your heart rate or rhythm. It means that your heart beats too quickly, too slowly, or with an irregular pattern. Most arrhythmias result from problems in the electrical system of the heart. If your arrhythmia is serious, you may need a cardiac pacemaker or an implantable cardioverter defibrillator (ICD). They are devices that are implanted in your chest or abdomen. A pacemaker helps control abnormal heart rhythms.
Generally speaking, the numbers refer to the parentages of Nitrogen, Phosphorus and Potassium, by weight, listed in this exact order and contained in the fertilizer. These numbers stand for the percentages contained within a specific package.
A fertilizer grade is used to determine the percentage by weight of plant nutrients in the product. For example, a 100-lb bag of fertilizer with a grade of 30-0-10 contains 30 lb of nitrogen, no phosphate, and 10 lb of potash. A 50-lb bag of the same product would yield 15 lb nitrogen, no phosphate, and 5 lb of potash. Knowing the fertilizer grade is important in determining how much fertilizer to apply to your turf.