Where does it say that minerals are hard on the liver, especially considering the liver is aided in its objectives from these needed essential minerals?? Also sea water is 98% Sodium Chloride with very little trace elements, this in itself can create an imbalance and may actually be safer in an oil but not necessarily as beneficial as one may assume.
All alkaline minerals should be supplemented with an acid, preferably an organic acid but in the case of Magnesium the Mag/Sulfate is preferable for the benefits Sulfur provides, but in the case of other alkaline mineral such as Calcium I find it preferable with a citrate or better yet fresh squeezed lemon or even raw Apple Cider Vinegar!
Supplementation plays second fiddle to obtaining essential nutrients compared to the way nature intended us to,through the foods we eat,with balanced ratios, but this is a challenge in today's world so if we are going to supplement we should try to imitate nature as much as possible!