Hach DR890 - eBay (item 260228687018 end time Apr-16-08 06:20:53 PDT)

This is a good little unit that can measure most any parameter an aquarists might want with excellent accuracy.

300-500$ vs 1000$ new is not bad.
You can use the Hach reagents, standards etc also or make your own.

Regards,
Tom Barr

Why would you need to pay that much to test? The AP tests work great. Freshwater planted tanks and even saltwater reef tanks don't need pin-point accuracy. Your eyes are the best tools for measuring.