its not bad advice, your being to extreme. if the ph is just a bit off my point is dont worry about. And were not talking about blue berries in soil either. I grow hundreds of plants from around the world and i use the same ph and
nutrient mix on all of them and have excellent results. lets assume the guy is not or any one is using non drinkable water if your using somthing else then we should know that. we have to have some standard on here to answer and help general questions.
and if you find drinkable water around the world you'll have pretty good luck in your hydro system. again watering dirt is not what we do on here and it adds to many vairables.