Dissolved Oxygen Meter with ATC, 0-40.00 mg/L Measurement Range, DO Meter with Electrode Filling Fluid and Anaerobic Water Calibration Powder

I got this for some upcoming aquaponics projects as I wanted to get more accurate results measuring the water for a range of things, including dissolved oxygen. The unit was pretty straightforward to use, and I honestly am not sure how accurate it is but it seems like the readings are fine. No complaints here

Entire wand must be immersed to accurately capture temperature of specimen. Will not return correct DO results if not fully into sample.

Stopped working after about 3 months

I got this to check the water in my nearby Lake and also the water I been producing in my home distiller (before and after distillation). Difficult to follow instructions but much help thanks to another reviewer. They provide a small amount of sodium sulphite powder to absorb residual oxygen to make a known blank. But fortunately sodium sulfite is cheap and easily available; don't bother trying to make your own by burning sulfur to get sulfur dioxide because you get some sulfur trioxide (becomes sulfuric acid) as a byproduct.Depending upon your need for dissolved oxygen measuring range available and exactness (accuracy) and repeatability (precision) you may need more than this starting type system but for cost this is entirely reasonable; the higher-level instruments cost many thousands of dollars.In conclusion: recommend. This may be all you need for your application(s) or help you understand some of the problems of measuring and help decide if you need more.

This GISNPA Dissolved Oxygen meter is a good, basic meter. It comes with electrolyte filling solution and 6 additional membranes, which is more than enough to last for quite a bit of use. I'll be using this to monitor a deep well to watch for casing cracks. Calibration in 100% air mode is quick and easy. Temperature quickly switches between deg C and deg F, and % oxygen or ppm is equally easy to change at the press of a button. A quick check of tap water provided a reasonable result, 5 minutes after opening the box. I've worked with laboratory DO meters for my entire career in chemistry and, for personal use, this meter does the job just as well as professional bench-top models. For those who couldn't keep a good calibration, try putting some water in the membrane cap (not where the electrolyte goes, but the protective cap instead). Bench-top meters usually have a DO bottle with water that you store the probe in, so storing a probe dry is the worst thing for the membrane. It would be nice if the mfg. would provide a link for additional filling solution, calibration powder, and membranes. Also, they should provide a Safety Data Sheet (SDS) to be fully compliant with OSHA regulations. Without the SDS, there is no safety information for accidental ingestion (it happens, with pets and kids in a household. Better safe than sorry).

OK, as many people says, the manual is somewhat incomplete with errors. But assembling the tool can be accomplished with this manual. 100% calibration is easy. 0% calibration is confusing as the manual says to use 30mL distilled water but the packet has big "250-mL" sticker. It's up to you if you want to use 30-mL or 250-mL but since the purpose of using it is to deplete oxygen in the solution, I would use 30-mL.Once I dip the probe in the water I want to measure DO, the reading will continue to go down almost endlessly (gradually slows down). There is no explanation on how to measure DO in the manual. Am I supposed to use the reading when the number is somewhat stable? Or do I have to wait until it completely stops? How much water/solution am I supposed to use for measurement? Those I guess I have to figure out myself.Other thing I noticed was 6 membranes that came in the package was bit dirty and also has wrinkles. I am not sure how much this will affect the reading. I have washed them with distill water and air-dried. I think wiping with paper towel etc. will scratch the membrane and cause erroneous readings.Anyway, assuming I am using it correctly, measuring DO was easy. The first recorded numbers seemed reasonable. I will continue to use it and see!+++After 1 week of use, I found the temperature is off all the time. I used two other thermometers and found this one to be about -0.2 to -4.8 degrees off. I don't know how the thermometer works on this tool and I don't think there is a way to calibrate it... As the temperature affects the DO reading, regret to say I think this device is unreliable. I'm still using it just to see ups & downs of DO.

The GISNPA Dissolved Oxygen Meter offers a convenient and reliable solution for measuring dissolved oxygen (DO) levels in various aqueous environments, particularly for aquatic life enthusiasts. Here's a breakdown of its key features and potential benefits:Pros:• Extended measurement range: Measures a wider range of DO (0-40.0 mg/L) compared to the standard range found in many meters, making it suitable for diverse applications.• User-friendly design: Allows for measurement and calibration without removing the electrode cover, simplifying the process.• Automatic temperature compensation (ATC): Ensures accurate readings across a temperature range of 0-50°C, eliminating the need for manual adjustments.• Clear display: The LCD screen with backlight provides easy visibility in various lighting conditions.• Auto power-off and low battery indicator: Promote efficient battery usage and timely device maintenance.• Comprehensive kit: Includes essentials like calibration powder and protective covers for extended use and reliable performance.• Wide range of applications: Suitable for monitoring DO levels in aquariums, swimming pools, ponds, aquaculture facilities, and various research settings.

These instructions are obviously translated very badly from another language. I am still struggling to figure out how to calibrate with the anoxic solution to zero.