you have no idea on how hard i tried to get mar-2. called 3 petcos and asked them for the sw version. they all said yes they have it, so i drive there only to find that no one can read the difference between salt and fresh. so after cursing out the 3rd manger and asking them how stupid can you be, they give me some crap in a blue bottle called melafix. it did nothing but make my tank smell. so after driving about 60 miles being an hour and a half late to work i got nothing to show for my troubles besides a dead fish, a smelly bottle and less patience for those at *****.