Epsom salt is magnesium sulfate. There should be plenty in salt water.About one seventh of the magnesium in seawater is present as magnesium sulfate. So you probably have about 200ppm epsom salt in your tank right now if your magnesium is on track at about 1400ppm or so.. Probably a good thing to use in a fresh water case.
I feed frozen every day. Note from the article the importance of skeletal matter for fiber. For me this would include exoskeltons from mysis brine, mosquito larvae, etc as well as nori,broccoli, and other vegetable matter.
