Holey rock; for it's pH buffering ability. Your rift lake cichlids require a stable high pH and holey rock is your best bet to attain and maintain proper pH.
BTW, I also mix aragonite into my gravel since aragonite dissolves faster to adjust pH after water changes. I just replenish the aragonite every 2 years.
BTW, I also mix aragonite into my gravel since aragonite dissolves faster to adjust pH after water changes. I just replenish the aragonite every 2 years.