I take Calcium Lactate by standard process at the moment. Its has a 5:1 calcium to magnesium ratio. But if you want straight calcium NOW has a calcium citrate powder that is very cheap, or you could make your own calcium with eggshells and lemon juice. Its really up to you. I know what the study says but i want to keep in perspective that we do need magnesium also. But Calcium maybe an overlooked factor in healing candida and its seems that everyone including myself may be making the situation worse by only taking magnesium.