Hello! My tap pH is 6 or below. I’ve been struggling with getting the pH up in my 10 gallon. I’ve added API pH up and crushed coral. At first the coral raised it to 7, but within a week, it was back down to 6.4. I can only assume it will continue to go back down until it’s 6. Any suggestions? It’s a betta tank if that’s important. Thank you!