As others have said, if your salinity is ~1.025 (definitely not 1.25), do not worry. That value is fine for a reef tank. Some people recommend slightly lower values for fish only tanks. However, I would recommend that you add your make-up or top-off water daily if possible. Whatever your salinity is, you want it to be as stable as possible. If you add water only once a week, you may be adding gallons depending upon tank size and evaporation rate. That amount of water will cause your specific gravity to change suddenly. You do not want that. If you add smaller amounts of water daily, the changes will be much less noticable to your creatures.