Train, some have said that. I have a 24 gal. JBJ Nano Cube and my xenia grows like a weed. I frag several stalks about once a month and it comes back in a fury. However, I have chaetomorpha macroalgae and some other wild macroalgae that grows in my tank and my nitrates are zero. Between the macroalgae and the xenia, they probably consume it as fast as it is produced and keep it at zero. For what it is worth, I have always read and heard that xenia prefer "dirty" water. Good luck!
:joy: