First off thank you Bill Cody for posting that info.

Could one of the pro's discuss the device that CJBS2003 posted a link to? Is the DO sensor accurate? I have been looking at similar devices for measuring o2 and they get crazy expensive. Is the one linked above reasonably accurate? Good enough for an amature?

Any and all thoughts are appreciated. Thanks for posting that link CJ.

JHAP
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"My mind is a raging torrent, flooded with rivulets of thought cascading into a waterfall of creative alternatives."
...Hedley Lamarr (that's Hedley not Hedy)