Chaeto growth

[Delphinus]

I'll second what Bassman said.

I find chaeto has to hit a sort of critical mass before growth becomes noticeable. Ie., I find if I move a clump from one tank to another it just sort of sits there. But a few months on and suddenly it stars doubling in size every week.

If it's new to your system it might just be at that point still. If it's not disintegrating on you then it's probably OK.