So I keep testing my water with the hydrometer to check the gravity of it. On the back of my Coral-Life Deep Six Hydrometer and where the preferred gravity meter arrow pointer should be which is between 1.023 and 1.020. I got the gravity level in the preferred area but my mom talked to one of the employs at Petsmart and the guy said to keep it between 1.024 and 1.026. So where is the general gravity level at in most tanks??? 8O