I hope your AI is looking a little better lately. I have just purchased a seaweed based additive that has many and various trace elements in it, particularly calcium and magnesium which will hopefully fix your problem permanently.
:: BioBizz
That should do the trick if your problems persist. NPK value 0.1-0.1-0.1 with calcium and magnesium at 0.1 and 0.2 respectively. All natural and organic as well, not as cheap as some as I payed about £9 for a 500ml bottle, though you only need to use 3-5ml per litre. As to where you would purchase this I just wouldnt know in your part of the world.
Keep it green.