Digital Dissolved Oxygen Meter, GIDIGI Dissolved Oxygen Tester with ATC, DO Meter with 9.84ft DO Probe Cable, Dissolved Oxygen Test Kit for Aquarium, Ponds, Fish Tank Range 0.0‑40.0 Mg/L

I got this meter to read the dissolved oxygen levels in my many fish tanks. They are all planted and should not have any issues with oxygen, but I had one tank that could not support even a few shrimp. After all of the basic parameters checked out I decided I should find a way to determine the amount of the oxygen in the tank. Reduced oxygen could indicate a chemical issue with the tank or a bacterial infection, or insufficient filtration, among other things.This meter comes with well-written and easily-understood directions. There are a few grammatical issues, but the manual was presumably written by someone who doesn't speak english as a first language, and considering this, it's well done indeed. If you follow the instructions laid out in the book the meter works exactly as intended. It is crucial that you perform both the zero and slope calibrations prior to using the device or the obtained readings will be meaningless.I found the meter to be accurate, especially when using the conversion chart for temperature that's in the book. When used qualitatively you can see if there are glaring issues with the oxygen levels in your tanks. I'm not using it to split hairs, a percent difference here and there isn't what I'm concerned about, so now that I trust the device I'll only be using the correction factors to spot check the meter.The probe has to be filled with electrolyte to work and is sensitive to damage and drying out, so this meter requires maintenance that standard pH and salinity meters don't. It comes with spare probes and spare electrolyte so when the probes ultimately are consumed you have plenty of spares to keep it going. You can also order replacements when needed.All in all this meter does what I want it to do and is relatively simple to use and maintain. If you have a need to measure the dissolved oxygen in an aquatic sample, this meter represents good value.

The media could not be loaded. It took a while to do this review as I had to get everything setup first.My purpose for buying this was to measure DO in homemade Meads, Beers, Ciders and Wine.First the basic - it operates with four cell batteries which is under the top cap (as shown in picture). The probe is separate on a 3 meter cable (it did not need to be this long for my purposes). The meter and probe arrive with protective cap coverings.To use is - remote the protective covers; replace probe cap with a oxygen absorbing membrane (it ships with identical but not working cap and has another protective cover on top of the membrane). Six such membranes are included but it is not clear when they should be replaced (maybe deep in instructions somewhere).To use it - one has to first calibrate it. 0% calibration has to be done only once but "air" caliberation has to be done prior to each use. It comes with 0% calibration solution.It reports both in % saturation and PPM on clicking of a button.Following instructions - both 0% and 100% calibration was easy and quick.Next came the testing part - First checked with a really old mead which felt like it was very oxidized. Sure enough - it showed about 15% DO. It takes a while to settle down to a stable reading (See attached video) and again you can switch between mg/L and %.Next (after rinsing the probe) - I switched it to Sparkling Water - and the reading went straight down to zero. That was a good sign on the range.Next - I tested another mead which was opened about 2 months back and there was about 1 oz left at the bottom of the bottle (i.e., quite well oxidized). The reading jumped to 32% right away. So that seems right as well.After using it - one needs to rinse the probe and it needs to be stored in electrolyte solution (Supplied)One thing I have not tested it is on beers - not sure if carbonation makes a difference in reading and also I would not know how accurate it is in that case in absence of another device to compare it with. Though the sparkling water I used to test it on - seems to work.But for the purposes of testing meads/wines it seems to work well.I did cut one point from review primarily because after unpacking it - I had to pack it back in the box. I would have liked it it came with a case. Probably 1 point is too harsh but it does not allow rating in partial stars. If so - I would rate this 4.5 stars.

This Oxygen tester seems to work, but I have no way to verify it. First of all, the instructions are a bit difficult to read, but you can make out the basics. They want you to add the solution to the cover testing thing then first use the 0-oxygen water to calibrate, but just opening the lid and stirring the 0-oxygen container adds oxygen to the water, so not sure how that works. Once you use the 0-oxygen container, it is then no longer 0-oxygen. Which means if you for whatever reason need to re-calibrate the unit, you need to figure out where to get 0-oxygen water from. Now to the testing itself. Add new solution and then run your test. Again, you must slowly move the tester around to get a proper reading, if you leave it still the reading will drop and keep dropping, but moving the tester gets you stable-ish readings. The problem is, you don't know how accurate it is, without knowing if your truly calibrated. With that said, the unit works, but I'm skeptical of the accuracy. Maybe, it's too complicated for me, I don't know. Lastly, it only comes with 2 containers of the solution and a few extra testing head things. I'm not sure where to get others or how many times you can reuse the head things.