Tell us more about your batteries, model, and amp hours. If that is your pair of GC-2's, take a specific gravity reading per cell on each cell on each battery.
Write down the date and each cell reading and post them up here.
Also describe the size, in mm, of the bubbles coming to the surface of the batteries. They should be 1mm in diameter, not roily boiling hot water action type bubbles, but little tiny bubbles coming up. Size of bubbles should increase slightly the higher you are charged, and or the higher or more topped out your specific gravity is. Tiny bubbles are good, they are stirring the electrolyte up, and making it homogenized for proper measuring with a hydrometer.