Just to add to what TKOS has said.
MArine mixes are high in Ca and Mg as well as a few other minerals and Sodium chloride. IMHO it would be better to use that than Straight sodium Chloride (Salt, freshwater aquarium salt, Food grade Sea salt, So on and so forth) In any case The cichlids would be better off with a mineral mix designed for their needs. Cichlid Salts are a mix of mineral salts not to be confused with straight sodium Chloride. You can come up with a DIY mix yourself, buy the commercial stuff, or buy one of several substrates designed to provide the necessary minerals.
Many people, Expert and novice alike do not understand salt and water hardness well. Hard water fish prefer (Usually don't need) elevated solids levels in their water. Salt will create this effect and many people use it without any thought to the long term effects, or the real chemistry of the natural waters. This is unfortunately fuel for the Salt myth which runs rampant in the hobby. Earthy minerals and metals will better replicate natural waters, increase solids and allow these fish to be healthier long term.
It has been a while since I ran the numbers, but the Sodium Chloride content in the saltiest of the rift lakes still comes out below 1/4 teaspoon per gallon. The rest of the chemical composition consists mostly of magnesium and calcium with many other trace elements in smaller quantities.
dave