why's my pH so low??

[Beverly]

Another thought occurred to me. We don't have any fresh air coming into our condo unless we open windows. In winter low pH was especially a problem, until we began to open our bedroom windows a crack and have a floor fan blow the fresh air into the living/dining/tank rooms. Do you have fresh air coming into your tank room? If not, high CO2 in the air could be a cause of your low pH.