American Marine Pinpoint Oxygen Monitor
Product Review (submitted on September 30, 2011):
I got this because dissolved oxygen levels are said to especially critical for seahorses-I have 4 and 2 pipefish in one of my tanks. My aquarium maintenace guy helped me to get the machine up and running. Once you get it going it is easy to use. Happily my levels on my seahorse tank were exactly within the recommended range. I plan to use the monitor when I start to culture copepods which are also said to be oxygen sensitive. My aquarium maintenace guy (he cleans and does water exchanges) is very impressed with the Pinpoint oxygen, pH and salinity monitors I bought.