My ph is 7.4 from the tap and moderately hard. Over a period of six months to a year. the natural processes that take place in the aquarium ,bring my pH levels to 7.0 to 7.2 To be honest, I don't recall exactly what water the keyholes require but am sharing what my parameters are and as stated, they did fine. They had an amusing habit of moving pebbles about in the aquarium on a near daily basis. Especially after gravel vaccuming, they would spend a considerable amount of time picking up pebbles with their mouths,and spitting them out at where they thought the pebbles should be.