I too am having the same problem though my tank is almost 3 months old. LFS sold me some Marine buffer to raise it to 8.3, this does work but it doesn't hold. I then bought some reef builder because my ALK was low and my PH has dropped again. I tested it this morning at 8.0 and i added somemarine buffer and it is now 8.2 - 8.4. What can i do to keep my PH to hold without having to keep adding buffer? I don't want to keep buying buffer week after week.