Well no. Like I said. Having species from hard and soft water isn't advised. They will slowly die and it could be painfully depending on the condition of your water...So perhaps I should go for 7.5 that way it is a bit of both. I was told when i took my water in I needed to icnrease the pH of the water so I got some pH solution that increases it.
The PH stuff they sell you can actually be lethal (sometimes). There are natural ways of raising and lowering PH/GH without chems.