The tank manufacturer says 125 gallon, but take out some of that 125 gallons for the air space between the water surface and the tank rim, and more doe the substrate and decor in there. It probably gold 100 gallons water.
The bottle of ammonium chloride says to add 4 drops per gallon. 100 gallons needs 400 drops. The bottle of ammonium chloride says 5 ml (ie one teaspoon) contains 100 drops. So 400 drops are 4 teaspoons. Even 125 gallons only needs 5 teaspoons. If you used a spoon you use to stir your coffee with, that probably wouldn't measure 5 ml. You need a proper measuring spoon.
You've added twice as much as you needed.
I would remove half the water and replace it with dechlorinated tap water.
The bottle of ammonium chloride says to add 4 drops per gallon. 100 gallons needs 400 drops. The bottle of ammonium chloride says 5 ml (ie one teaspoon) contains 100 drops. So 400 drops are 4 teaspoons. Even 125 gallons only needs 5 teaspoons. If you used a spoon you use to stir your coffee with, that probably wouldn't measure 5 ml. You need a proper measuring spoon.
You've added twice as much as you needed.
I would remove half the water and replace it with dechlorinated tap water.
