Not sure what the deficiency is. Just doing the regular dosing. Two teaspoons lime, two teaspoons kelp extract, one teaspoon iron.
Usually, when the fish get a bit sluggish, the water pH is getting too low. I did not have time to check the pH today, but saw the fish showing slight signs of sluggishness. Added two teaspoons of lime to raise the pH. Added one teaspoon of iron for the plants.