As far as brands go, you can't do any better than YSI. I would recommend a YSI 55 as a good general purpose meter that is durable. That's what most professionals use, myself included, and they work well. You don't want to let the probe dry out, though, and the membrane will need replaced occasionally.
You might check out this website
here and see what Randy Rushin can get you a new meter for. You might mention that you got his name off of Pondboss. I've been trying to get him to sponsor the site for some time.
Alternatively, I have an extra YSI 55 with a 12' cord that I no longer need. I would be willing to part with it for $225 shipped. You can check the price of a new one as well as its features
here at one of this site's sponsors.
