Equine America Magnitude Powder. Keep your horse happy and help to reduce nervous tension with Equine America Magnitude Powder. Offering a complementary mineral feed, Magnitude Powder helps to support healthy magnesium levels which plays a role in the healthy of nerve endings and fibres as a lack of magnesium may show in nervousness or tension. Magnitude offers a highly absorbance form on magnesium and should be fed daily to promote healthy nerve tissue and to encourage good behaviour and reduce nervous tension.