Looking at pH by itself is a big mistake if you're going to try adjust your water parameters. If you want to start dosing your water for whatever reason then take the time to learn about hardness, conductivity and TDS so you know fully what you're doing and more importantly why you're doing it.
If you are having problems with your pH crashing you almost certainly have low hardness, and if you want to raise your pH (or keep it more stable) without learning about water parameters then you could do so by adding a small amount of crushed shell or crushed coral to one of your filters monitoring the pH. Just start out small and slowly increase it until you reach the desired level.