Water Soluble Mineral

Does anyone use or heard of anyone using water soluble mineral for water troughs or water tanks for deer?

If so, what brand mineral or type mineral do you use?

Further, we are protein feeding. With this being said would adding mineral to the water supply help or is the protein feed adequate?

I researched a few years back and found no one had it at all. What I have found is if deer are getting the right protein/mineral mix then they will not need mineral. They get a lot from the soil also. I have seen a man take and let a water trough just seep over the edge to keep the ground wet and give fawns and birds a little water puddle. He took loose minerals and added to these spots and got a lot of consumption but had to quit since he was in a high anthrax area and had an outbreak that year.