If thats your situation, depending on how much money you have, I would definatly use kalk, or a ca reactor. I have nearly the same problem, the products are available to me, but I dont have the money to use them, so with my horribly limited budget, I switched to dripping kalk. Im getting better results, and it costs less than half of what I was doing before. If youve got the cash, I would get a ca reactor, if ya dont, set up a kalk dripper, so you could just buy a large bulk ammount of kalk for cheap, and your ca and alk demands are taken care of for a long time, giving you ample time to find another source of calcium before it runs out. As I stated before, if you can get brightwell kalk+2, use it, It doesnt keep up with the mg demand perfectly like it claims to, but it does have a significant impact, and and will save you some money.