Hello,what are the hardness levels in your tapwater? In my experiance adding coral gravel has little effect on the hardness when fish are present,you will need to use a chemical buffer to raise the GH and KH in soft water,if these are at the proper levels the PH should rise.There are two ways to raise this,you can buy a Malawi salt mix,or you can make your own,have a look on www.malawicichlidhomepage.com,there is a salt mix on there.On mixing water I would buy a TDS meter and aim for about 350 to 400 ppm,this is a more accurate way of measuring total hardness levels than those drip tests and will work out cheaper in the long run,regards Ray.