My issue with leathers is their chemical warfare. In my old 125 I had 3 toadstools. 1 was 13" across. Every sps or lps I put in that tank died. Zoas, palys, rhodactis survived. Nothing else. Ran carbon 24/7. Then I ran across an article about toadstools and chemicals. One issue I think was my clowns thought it a good substitute for a nem and prob. kept it irritated. As soon as I removed the leathers, picked up some lps, they survived. I got my new tank because I thought the 125 had bad rock or something wrong with it (aside for the powerheads all dying). I know now my biggest issue was that leather. Now those lps in my new display are thriving and growing . So no leathers in the new tank though I have a small one my bil gave me. It gets big it goes into the 45g.
Exception would be a weeping willow which can also go in the 45