Hi all. Can I ask you all who feed magnesium where you buy it from? Just interested in the most cost effective/best way of doing it. Have been buying mine off ebay but I do seem to be feeding quite a bit (4g per 100 kg of boadyweight = nearly 20g a day for us) however I notice Equine of America's Magnitude is only 5 g a day and £15.99's worth lasts 6 months? I assume the latter is a more condensed product? Sounds pretty good. Many thanks!