I would think gravel would be worse than sand to ingest. I know bichirs can sometimes get intestinal blockages from gravel and it's sometimes suggested to keep them on sand or bare bottom. Haven't seen it with cichlids myself.
Thanks all. The filters aren't an issue, running a sump and FX5 and there is currently 9 big altifrons in there messing it up and I've never had a problem with it being sucked up.
Its quite deep at the moment, and I will certainly thin it down a bit if I leave it in there with the new stock, and I stir it weekly when doing water changes to avoid any pockets building up too long.
I have tanks with both and I def like he sand more it is easier to clean and is a better place for Ben. Bacteria and I think that the fish like it more too