If it helps, this is where I got the dry ingredients for my fertilizer mixes. The dry ingredients go a long way and are cheap/last a while. https://nilocg.com/collections/dry-fertilizers
I don't know how safe they are to use in a reef tank, but my planted FW tanks and the mangroves seem to like it just fine.
I don't know how safe they are to use in a reef tank, but my planted FW tanks and the mangroves seem to like it just fine.