It can be used by animals that eat moss, such as shrimp, to control moss. Animals that can swallow moss include moss-eating mouse fish, Macrobrachium nipponense and snails. Elves, masters of eating algae, do not grab food, and are the number one tool in freshwater aquariums (hay pots).
I wonder what your water is for.
Ferric chloride reagent is generally added for water treatment and purification.
Ferric chloride can be used to purify water.
The moss on the water tank should be of poor water quality.
There are too many nutrients in the water, which leads to the proliferation of algae.
It is best to brush the water tank clean before adding the reagent.
Solve fundamentally