low alk can cause all sorts of issues for sure, don't know if it's going to kill fish though? Corals don't like it thats for sure...
As for raising it you can use the store bought buffers but in the long run doing that is kind of expensive. I use bulk chemicals that I buy from the local frag store. I buy 5 pounds of Sodium Bicarbonate for my alk, Calcium and magnesium, all in powder form. This will last me at least 4 months of daily dosing and costs me about $15. If you buy products you'll be paying 20 times that for basically the same chemicals already mixed...
But its way easier to just put a capfull of part a and a cap of part b in your tank then figure out ratios and mix yourself...lol I'm a dork though so I don't mind...