Hi, thanks for the reply. I change 40% of the water every week. My tank parameters were very stable until recently when I got new GBRs and they had fin rot. I used an antibacterial medication (Furan-2) to cure the fin rot, but the antibacterial meds killed all my bb sending my tank into a mini-cycle. I had an ammonia spike, a nitrite spike, and my pH dropped really low. I did daily water changes until everything was back to normal except the pH. So really, me using crushed coral at this point is the best option. I am aware that crushed coral is a buffer that raises KH and that is what I want, I want a stable pH of 6.8. It was at 5.0 and not rising even with daily water changes and had been that way for 2 weeks.
So to answer your question, yes I did try just changing my water. The issue is not that simple.