I want to give a "heads up" to all that use a Sea Test type of Hydrometer. This type uses a foating pointer. With time the pointer can accumulate calcium and other deposits. This can cause false readings. I recently replaced mine and when I retested my water I was reading a specific gravity of 1.028 ! All the while my old Hydrometer was reading 1.024. The manufacturer suggests rinsing the Hydrometer out with vinegar.