A Community and Forum For Aquaponic Gardeners

Dissolved Oxygen

I've tried several methods of testing dissolved oxygen (DO) including a liquid test kit which was hard to use (Salifert DO test kit) and a MilWAUKEE MW600 tester (cheapest tester you can buy).

DO is a bit of a challenge and I can see why many don't bother with it. Reference solutions like zero oxygen can be contaminated easily. Test kits like the salifert use colors that are so close together, it's hard to read with any confidence.

The MW600 meter seemed to work ok initially but now seems unreliable. I contacted Milwaukee but they didn't offer any good solution. I can't zero it and after much effort when I did zero it, the readings were not correct.

Does anyone have any advice on DO meters? Hannah instruments seems like its easy to calibrate and looks much better than the MW600 with a price to match.

I do run air pumps in my system and have a pump cycling at least twice per hour - I have lost quite a few fish and I like the precision and peace of mind knowing exactly with my DO levels are, rather than leaving it to guesswork.

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Permalink Reply by Rob Nash on September 23, 2013 at 7:39pm

Had the same exact experience with the mw600.. I gave up on testing... and just crank the air.