Depending on analysis there may be a ceratin amount of "filler material used in a fert blend. Example 24-5-11 is only 40% nutrient by weight. So a 50lb bag is only 20Lb of nutrients. The other 30 lbs is either a component of those nutrients or filler material to get to the 50 lbs. So if your custom blending why not use a maintenance qty of lime to hold pH and only sell lime as needed for those that need more than the maintenance qty. It would save a trip for just liming.