[Xymon] Configure per-host filesystem threshold

I'm new to Xymon, have set up my first client monitoring config, and haven't gotten per-host filesystem thresholds to work for that host yet. In /etc/xymon/analysis.cfg, I've got these lines:

HOST=my.hosts.fqdn DISK /disk/data 96 98

But my 95% filesystem-full condition continues to come up as a red alert. I've played with a few different syntaxes, wildcards, and other config files. This looks to me like the right way to do it... Feels like I'm overlooking something really basic here. Thanks,

• Chris [Running Xymon 4.3.25 on Ubuntu 16.04.1. New to Xymon; used to use Big Brother years ago.]