If it were me, keeping S American species, I'd be using peat or some other tannic acid producer to bring tannins to the systems water. The tannins have an anti-bacterial component, and I believe because many S American cichlids come from naturally tannin infused water, they are less resistant to the bacteria that cause HITH.
Water change water containers could have bags of peat suspended in them, much like giant tea bags to be mixed with tap when water changes are performed, or have a constant drip of concentrated tannin infused water.
Water change water containers could have bags of peat suspended in them, much like giant tea bags to be mixed with tap when water changes are performed, or have a constant drip of concentrated tannin infused water.

