I've been using Caribsea African Cichlid Mix for years . They have several color and size options and all have a large portion of crushed coral in the mix to help buffer. It keeps my mbuna tank at 7.8 without any additives.
I've always used pool filter or play sand, but I've always had hard water as well. If you have soft or acidic water, crushed coral/aragonite, oyster shell or dolomite gravel or sand may help buffer the water to maintain pH once you get the water up to the right pH. Regardless of what you choose, make sure you rinse it thoroughly before use.