GHS Super lemon haze

Been a bit of a naughty week really its not actually been a week but Oh my it felt like it. So after i went abit daft on the defoliation things was okay. we got growth. I noticed that the plant had started to get a purple stem and thought this was a good thing even tho common sense told me lemon haze shouldnt be purple, though it is a clone so things can happen. I stupidly changed the light cycle to a 12 on 12 off. The branches went all woody and dry feeling which then made me start to worry. the leaves faded and started to go yellow so research time it is. Phosphorus was my initial thought or nitrogen. But there shouldn't really be any as ive used enough feed for a heavy feeding plant. the plant was to put the flowering feed in mid week which I thought might help the situation because its lacking something. I put in quite abit of biobloom, im planning for a 9 to 10 week flowering cycle so I used roughly 50g which I will top up with some more in 3 weeks time. watered and checked the PH which was at 6.2 and for coco i believe that to be quite good. the next day I got a nice clear sign to the real problem. a brown spot on the leaf. CALCIUM! u little bugger. I thought my water here where I live was hard but how wrong was I? might have made quite the error and affected the whole grow cupboard with this stupid beginners mistake. Straight away I flushed with calcium water at 240PPM and over the past 3 days if seen a rise. things r improving thank goodness. lets hope for a nice easy ride out for the rest now.