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Recently I bought two digital test meters from China (one for TDS and the other for PH). The temperature displayed on the TDS meter was different from a non-digital thermometer I got from a top fin tank kit. Because of this, I am starting to doubt the accuracy and quality of the TDS meter. Is there any way I could test the accuracy of the TDS meter without RO water? If I do have to get a new test kit, what test kits and brands do you recommend for Caridina shrimp?
Thanks :)
 

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Recently I bought two digital test meters from China (one for TDS and the other for PH). The temperature displayed on the TDS meter was different from a non-digital thermometer I got from a top fin tank kit. Because of this, I am starting to doubt the accuracy and quality of the TDS meter. Is there any way I could test the accuracy of the TDS meter without RO water? If I do have to get a new test kit, what test kits and brands do you recommend for Caridina shrimp?
Thanks :)
Hi @FishyFishyFishyPlantPlant

Digital test meters are being churned out by the bucket load. And, the price of these meters is a strong clue what to expect from them. Technically-speaking, so-called TDS meters contain simple electronics. pH meters are more complex. In order to get some idea of what to expect, I would suggest a minimum price of $45 for a TDS/Conductivity meter and $80 for a pH meter. These are just ballpark figures. I quite like the Extech range of products and, no, I have no commercial interests in this company. Hanna Instruments is another possibility.

As for checking the accuracy of your TDS meter, consider purchasing a calibration solution.

Anon
 

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Test strips are nearly useless when looking for any accuracy, but @Anon is not suggesting test strips. What he/she is suggesting is the 342 ppm calibration solution for TDS meters, such as this: Calibration Solution
 
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An in-line TDS meter for a nice RO/DI system will run you between $20-$30. I just bought an unbranded hand-held one that Hanna rebrands from the OEM for $5 on fleabay. Anything $5-$15 will work well for you if you spend a few bucks on calibration solution or known TDS water. I've had some cheap ones going for nearly 20 years. Still good as new. I calibrate only when I think about it. (Maybe once a year? Maybe twice?)

Right now you can grab a good one from Marine Depot for about $5, as they're going through their liquidation sale.

For pH meters, everyone is right. Those are gonna be expensive. Decent ones use probes that that remain in-tank. They range from $100-$250 and have to be calibrated monthly. Hand-held meters that are decent have to be kept in a storage solution and calibrated before each use - so I avoid them entirely.

But in terms of liquid test kits? Brand does matter and it depends upon what you're testing. Not everything is created equal and not everything serves everyone the same.

API pH kits may work well for the average planted tanker because they do well enough. But I keep sensitive shrimp species and like something with a more reliable range, so I tend to gravitate toward Sera. Only a couple dollars more expensive in North America but worth it for me. I prefer it over digital monitors. Same for gH and kH kits. It's all a matter of preference and what you're trying to accomplish.

P.S. Just say no to test strips. Tend to be inaccurate and the amount of plastic waste is bonkers.
 
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