# Question: Substitution for conductivity meter

Ag8n asked on February 12, 2018 00:48
357 | 2 answers | #15716

Is there a reason why an aquarium type TDS ( Total Dissolved Solids ) meter couldn't be substituted for a conductivity meter?

Granted, they are no where near as accurate as a conductivity meter. But...They are dirt cheap and they do indicate dissolved solids.

Any help would be appreciated. Thank you.

Hi @Ag8n, Do you know how the aquarium TDS meter works? Maybe it really is just a super cheap conductivity meter?

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I think it is. Was hoping someone was more familiar than me. Different websites talk about charge and others about conductivity, which can be two different things. Tell you what. I know a wastewater plant manager and lab equipment salesman. Let me touch base and see what I find out.

Check out:

Https://www.hydroponics.net/lear

All tds meters are conductivity meters, but according to the article, they may not all use the same conversion factor. There have to be some that still display conductivity.

Sorry. Truncated the internet address: Https://www.hydroponics.net/learn/debate_over_ec_and_tds.php

I checked Amazon. There are several tds meters that also do conductivity for a price of under $20. Since a scientific model lists for about$1000, you wonder what differences there are between the instruments.

wow!!! This is very cool. Here's an amazon link: https://www.amazon.com/s/?tag=duc0c-20&url=search-alias%3Daps&field-keywords=tds%20aquarium

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I love this idea. Here are some leads on connecting a TDS meter to an Arduino, if that's what you're interested in:

https://forum.arduino.cc/index.php?topic=22175.0

This one for \$24 looks optical, for sure, so not conductivity-based:

https://www.amazon.com/uxcell-Suspended-Particles-Turbidity-Detection/dp/B01481JSCM/

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