Good tofu is really hard to come by where I live, especially silken tofu.  I want to try making my own tofu. There are tons of recipes online. BUT, some of the coagulants (gypsum, or nigari) are also a bit hard to come by. I don't want to use epsom salts because they can cause a grainy tofu.  Will it be possible to use agar in this instance? 
At the very least, transfer to a food storage container (smallest possible) and cover...for more than a day or two, Ziploc bag, with as much air removed as possible (use water displacement method)...or vacuum seal.   