My refugium's cheato seems to have portions (mostly the edges) going kind of brittle on me. Where it used to be one big mass, now moving parts results in breaking off lots of little bits that are starting to accumulate on the refugium floor.

Anyone have any ideas about what might cause this?

*starts to sing*

"Lemme tell you 'bout the birds and the bees and the flowers and the trees....."

It fragments in place of a typical sexual reproduction. Keeping it trimmed and turned will help with this.