You used mineral water?,... or distilled water?...
Should be distilled...
Mineral water is kinda' the opposite...
...
If you're using a trickle charger (300 to 500 ma) on a dead battery, it'll take fore ever,... use a 1 or 2 amp... 2 being preferred... more not recommended.
Battery tips..Charge dead batteries with a charger rated at 2 amps or less.
6 to 8 hours @ 2 amps
10 to 16 hours @ 1 amp
20 to 30 hours @ 1/2 amp