The iron content in seawater should be maintained at 0.01-0.1 mg/L. Iron is not only a nutrient for the single-cell zooxanthellae produced by corals, but also a nutrient for the brightly colored bodies of sea fish and invertebrates. When the iron content in the water is too low, the algae and invertebrates in the aquarium will become lighter in color. Generally speaking, when the iron content is less than 0.01 mg/L, liquid iron should be replenished in time to maintain the stability of seawater quality and the normal growth of invertebrates.

About the importance of iron in saltwater aquariums