No need for salts, you just need something to buffer the water. You can so this with crushed corel. I have crushed coral in my filter in a nylon stocking. I don't add anything else to my malawi tank just water conditioner when I do water changes.
It is a good idea to add some salt. The reason being most of the bugs that cause diseases are single cell and when adding an amount of salt these organisms cannot cope with the sudden fluctuation and the salt therefore helps with getting rid of these organisms. My fish supplier suggest a table spoon per 100litres. It does also help if you are battling with the water quality in the form of PH control. Its greatest benefit though is in disease control.
I would also suggest a sandy bottom as all my fish spend quite a bit of time sifting through the sand shortly after being fed.
My penny's worth.