the ranges are, i think youll agree, quite wide!
the idea is during flower the more P that can be absorbed the better! there fore to allow the ph to start at 6,5 and to drop over the next few days to 5,7 then hit it back up to 6,5 aagain!
this way the highter PH allows for more absorbtion of the P whilst the falling PH will allow for the other elements to be absorbed,
the prime pH for flowering is 5.7
however in the grow cycle the PH increases so the sollution is set at 5.5 and allowed to rise to 6.2 , this way thePH range is always within the requirements of the plants needs and in easy!reach for the plants!
the varieing PH is a good thing if controlled within certain parameters!the idea of altering the ph range is to optimise the easy accesability of nutrients to the plant! as and when the plant requires it.
also the ph as mentioned will rise in grow, and fall in flower!
there fore it makes sence to start at the opposite ends of the scale! in turn optomising the ph by natural process, altering the same too frequently, by adding PH corector, and trying to maintain a reading of 5.7 constantly!will only lock out nutrients and worsen the quality of the water!
hope this has been of some help!


welcome to a world of endless possibilities,,,,,hydroponics!