I was feeding a coarse sea salt before which was organic and pure and really not expensive. I am aware that the mineral contents may differ greatly

Hi Rachel,
Organic and pure doesn't mean there are no contaminents. Arsenic is organic and pure and is many times found in sea salt but not something I would want to be ingesting. The reason to use table salt is so that you know exactly how much sodium chloride and iodine you are feeding and so you know that your horse is getting enough of both of these essential nutrients.
Would you please add the year you joined the list to your signature in future posts and delete most of the messages you are replying to. This helps everyone find new info faster and helps the volunteers to getbetter info to you. Thanks.

Lavinia, Dante, George Too and Peanut
Jan 05, RI
EC Support Team