How do we measure DO? As I am filling in my pond, I am ejecting the water from about 2 feet up creating some O2 in the water, but not much. I ordered some 9" diffusers from diffuser express yesterday, and plan on beginning the process of building a diffused aeration station or two. I would like to monitor the "before and after" numbers for reference.

Usually one would use a DO Meter, but they can get expensive. A few people on the forum have different brands. IIRC Milwaukee is one of the least expensive brands. The lower cost unit's lack in features like altitude, temperature and salinity compensation. They may also be less accurate.

Another method is Titration. Not too expensive, but needs to be done quickly and carefully. May have to practice a bit first.

DO Titration

LaMotte is one of the leading brands. If going this rout, you may want to browse around and see if there are any other water parameters you would like to consider. May get a better price for an Aquaculture kit.

YSI 550A meter

Check Hatch as well. They have a new type IIRC.

Thanks guys, checking em out!

Hach.

Top dog's are going to be Mettler Toledo, Rosemount and Hach for meters. Pretty expensive!

YSI, Hanna and Extech are in the reasonable range for a handheld meter. (under 1K) I personally would go with Hanna or Extech.

With the Titration method, I would still stick with LaMotte! Their methodology/technology is accurate enough to calibrate DO meters, but it has to be done correctly.

Hope I did not give you a headache.

Let us know what you come up with.

Yes Hach. see this one $$$$$ http://www.hach.com/guides/HQdMeters/pr-guide-HQdMeters-DO-en.jsp

Thanks Eric!
Now I'll be reading all the new Hach manuals tonight!

They sure have some nice stuff!!!