Low Ph

I am plagued with low ph (7.6-7.9) but all my other parameters are fine. I was bothered a while with very high alk(13.0-13.5) but it has leveled out at around 8.7. Is there anything you can add to raise ph without causing the alk to skyrocket? I have tried IO Sea Buffer but the only difference I can tell with it is that alk goes up.