To give you a comparison of the composition of both: You carry about 1 scoop of 2,5gr per day, that is 2500mg product (Magnesium or Electrolytes). Converted to mg your horse will be given 2500mg of Magnesium when giving PharmaHorse Magnesium. The amount of magnesium used in the electrolytes is 18 grams per kg. Converted to 2500mg of electrolytes per day, your horse will receive 45mg of Magnesium when giving PharmaHorse Magnesium. Giving Electrolytes is therefore no substitute for the Magnesium that you usually carry. It can not hurt to give Magnesium and Electrolytes together.