watering questions

[oscar freak]

so i'v got my orchids for a couple of months and i havent
killed them yet im very chuffed.i'v been doing lots of reading which is sometimes a bad thing because now im getting conflicting stories.as stated in a seperate thread i live in jobur south africa its the middle of winter here now and i'v got cymbidiums buds just about to open and a dendrobium with its last flower.after nearly killing the dendro with kindness iv settled down and have been watering all my plants once a week with my fish tank water which is basically aged tap water with a high ph.i have the cyms in a green house suspended over a water tray for moisture the dendro is indoors and is spritzed with the same water everytime i come across it which is usually in the evening.they all seem to be doing fine but now in my efforts to do all i can for them i bought distilled water because i read somewhere that cyms dont like their water full of salts etc but then when i read somewhere else it says not to use distilled water for dends?i also got me some liquid fertilser 49.2:33:52 5ml per 1L of water was thinking to half the measure and use as my weekly water/feed and in my spritzer bottle.is this ok or should i stick to the bottles instructions of twice a month?