Precision Hydration's low calorie effervescent electrolyte tablets come in different strengths to match how you sweat. PH 1500 is their strongest electrolyte drink and it is typically used by athletes aiming to start well hydrated and recover faster after intense exercise. It is also used during exercise by heavy/salty sweaters. PH 1000 is a strong electrolyte drink typically used by athletes with moderate to high sweat/sodium losses and those exercising in hotter/humid conditions. PH 500 is a moderate strength electrolyte drink typically used by athletes with low to moderate sweat/sodium losses.