Try Epsom salt or if too much of an hassle try green house feeding powder it's well complete ! And u r welcome http://www.powderfeeding.ch/store/
Half strength shouldn't be burning them. Make sure you are mixing correctly. Posting pictures of your whole plant would help us, help you. We can't diagnose a problem from one leaf. You say the plant was nute burnt but that leaf shows a deficiency.
Sorry to invade ur tread , my plant is giving me hell too tried it all still don't know what the problem ! Maybe someone could help !