I have a tap water pH of 7.8 and have really never seen it be an issue with simply keeping healthy fish. On the other hand, I have almost no ability to breed egg layers other than my rainbow cichlids. If you are looking at breeding, try a mix of rain water with your tap water to lower the mineral content in your tanks. Chances are that a pH of 7.5 reflects some rather hard water with a high mineral content. Even my RO water has a 7.8 pH, so pH alone is a poor indicator of mineral content but it is not a bad first indication of what your tap water might be like. If you really want to breed soft water fish, invest in a TDS meter for around $20 on sites like e-bay. The idea is that you want to really know what the mineral content of your water is and you really can't measure that with any confidence short of having a TDS meter. I find that mine lets me gauge how much rain water to mix with my tap water for the one tank that I try to keep at under 100 ppm of TDS, so that my cories in that tank can breed.