@PsyCLown indeed it would be in the long run, just for feeds i use about 10L per feed, twice a week, refill my bottles once a month, so i spend about R100 a month on RO. its about R3500 for a good RO system, min. so it would take 3 years to recoup, in between there are diaphragms and filters you need to keep changing too. i have looked at it but figured the cost vs the inconvenience - the bottles win for now. will look at it again in the future if i expand my grow. In the meantime i've got more important things, on which seems like a never ending list of upgrades, to do in my grow room.
@iHigh so what i would do is flush with Ph'd tap water, what is the ppm? then run like the last 10L through each pot with RO, also ph'd, with the calmag & h2o2 (go like 1%), then final 1/2 strength feed wash through, ie runoff. Your plants can get chlorosis from too much chlorine, so you need to make sure its below max 300ppm.