Best TDS Meters for Aquarium (Reviewed 2021)

Updated on January 13, 2021 by

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What does the term TDS stand for especially when we talk about TDS levels in the aquarium water?

Our tap water contains plenty of organic and inorganic materials in molecular form and using a TDS (Total Dissolved Solids) meter we can measure the quantity levels of such materials. To name a few such materials: GH, KH, nitrate, nitrite, chlorine, etc.

To monitor and measure salinity levels, you might be interested to check out our article on the best salinity refractometers.

Since those can be found in our tap water in molecular forms, TDS, or Total Dissolved Solids, can be in other words explained as the substances that can not be collected up by aquarium filters.

Aquarium filters will only collect what comprises TSS (Total Suspended Solids), which includes material things such as plant matter, fish waste, or some fish food leftovers.

Water clarity and the photosynthesis of aquarium plants can be significantly decreased by high TDS levels in your aquarium. Having the right TDS levels in your freshwater or reef tank can be initially achieved by using one of the best RO/DI water filtration systems.

What a TDS meter basically does is measuring the electrical conductivity of the water, and then calculating the TDS water levels based on this. Let’s go through our list of carefully selected TDS meters for aquariums.

Best aquarium TDS meters compared

ImageProductFeaturesCheck Price
Best TDS Meter for Aquarium
HoneForest TDS, EC & Temp Meter
HoneForest TDS, EC & Temp Meter

Display: large and easy-to-read LCD
Functions: TDS, EC and Temp Pen 3 in 1
Automatic Temperature Compensation (ATC): Yes

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High Accuracy TDS Meter
HM Digital TDS-EZ Meter
HM Digital TDS-EZ Meter

Display: large and easy-to-read LCD screen
Hold Function: Yes
Auto-off function: Yes
Measurement Range: 0-9990 ppm

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Runner Up TDS Meter
Hanna TDS Meter
Hanna TDS Meter

Range: 0.0 to 99.9 µS/cm
Resolution: 0.1 µS/cm
Accuracy: ±2% F.S.
Calibration: manual, one point
Temperature Compensation: automatic from 0 to 50°C (32 to 122°F)

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Good All-round TDS Meter
TDS Meter Digital 3 in 1
TDS Meter Digital 3 in 1

Display: large and easy-to-read LCD
Functions: TDS, EC and Tempe Pen 3 in 1

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Sleek TDS Meter
HM Digital TDS-4 Pocket Size TDS Meter
HM Digital TDS-4 Pocket Size TDS Meter

Display: large and easy-to-read LCD screen
Hold Function: Yes
Auto-off function: Yes
Measurement Range: 0-9990 ppm
ATC (Automatic Temperature Compensation): Yes

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Top Tech TDS Meter
HM Digital AquaPro TDS Meter
HM Digital AquaPro TDS Meter

Display: large and easy-to-read LCD
Functions: TDS & EC Pen 2 in 1
Automatic Temperature Compensation (ATC): Yes
Digital Calibration: Yes

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Top Quality TDS Meter
Lxuemlu Professional 3-in-1 TDS Meter
Lxuemlu Professional 3-in-1 TDS Meter

Display: large and easy-to-read LCD
Functions: TDS, EC and Tempe Pen 3 in 1
Automatic Temperature Compensation (ATC): Yes
Auto Off & Hold Functions: Yes

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Best In-line TDS Meter
HM Digital In-Line TDS Monitor
HM Digital In-Line TDS Monitor

Measures TDS: Inline & Outline
Ideal for: RO/DI systems
Auto Off Function: Yes

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Value Pick TDS Meter
iSpring 3-Button Digital TDS Meter
iSpring 3-Button Digital TDS Meter

Display: large and easy-to-read LCD
Functions: TDS & EC Pen 2 in 1

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High Brightness Display
TDS Digital Water Test Meter
TDS Digital Water Test Meter

Display: large and easy-to-read LCD
Functions: TDS, EC and Tempe Pen 3 in 1
Automatic Temperature Compensation (ATC): Yes
Auto Off & Hold Functions: Yes

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Good Value Set
Pancellent TDS, PH, EC & Temp 4 in 1 Set
Pancellent TDS, PH, EC & Temp 4 in 1 Set

Display: large and easy-to-read LCD
Functions: TDS, EC, pH & Temp 4 in 1
Auto Calibration: Yes
Auto Off & Hold Functions: Yes

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1. HoneForest TDS, EC & Temp Meter – Overall Best TDS Meter with ATC for Aquarium

High Accuracy
HoneForest TDS, EC & Temp Meter 3 in 1 - Overall Best TDS Meter with ATC for Aquarium

To achieve high levels accuracy, the HoneForest TDS meter is equipped with a premium quality titanium alloy probe, and reliable Automatic Temperature Compensation (ATC) which ensure readings will always be accurate at various temperatures.

It is a professional TDS, EC and temperature pen 3 in 1 and comes upgraded with big backlit LCD for easier reading, and auto-lock function for easier use.

Just turn on the TDS meter and stir water gently, then stabilized readings will be auto-locked on LCD in seconds, and the tds ppm meter will shut off automatically after 2 minutes if it’s not used.

Whether you need it to test drinking water purity, or to monitor if your Reverse Osmosis (RO)/DI System works properly, you will certainly enjoy this great TDS meter for your aquarium.

PROs
  • Very easy to use and cost effective
  • Large digital readouts
  • There’s no need to do any calibration
  • Very positive reviews from existing customers, exceeding their expectations
  • Includes a nice portable leather bag
  • 3 years warranty and 90 days money back guarantee is also offered
CONs
  • Cannot test pH

2. HM Digital TDS Tester – Top Quality and Accurate TDS Meter for Aquarium

Top Quality
HM Digital TDS-EZ Water TDS Tester - Top Quality and Accurate TDS Meter for Aquarium

The HM TDS meter (aka ppm pen, nutrient tester, tds stick) is an inexpensive and convenient digital meter to check your overall water quality in no time.

With the push of a single button, the TDS-EZ will tell you your overall water purity level, which will be displayed on the screen in ppm (parts per million).

The lower the TDS level, the purer the water, with 0 ppm being pure H2O. The TDS-EZ is great for checking your tap water quality, or knowing when to change a filter for instance.

Although the meter does not test for biological contaminants, the TDS-EZ is a great tool for drinking water, water filtration and purification, hydroponics (test your nutrients), aquariums, RO/DI systems, pools, spas, and more.

PROs
  • Convenient and simple to use
  • Very cheap and durable
CONs
  • Customers complained the meter is not properly calibrated from factory

3. Health Metric TDS Meter Digital 3 in 1

TDS Digital Tester - 3 in 1 ppm EC and Temp

Measure your water quality within seconds, by Simply dipping the meter into the water and locking the results on the screen. The included easy to follow instructions make this factory calibrated TDS meter super convenient to use.

The advanced 3-in-1 smartpen combines TDS, EC, and a temperature meter for improved accuracy.

With an Automatic Temperature Compensation and the measuring range of 0-9999 ppm +/- 2%, it is an extremely useful TDS meter for your saltwater aquarium.

It is a very cost-effective TDS meter to regularly measure the effectiveness of RO/DI systems, water quality in pools and marine aquariums, and much more. The strong Titanium alloy probe keeps it functioning for many years to come.

PROs
  • Automatic Temperature Compensation (ATC)
  • Easy to use and convenient price
  • TDS meter suitable for both cold and warm liquids
  • Firm and durable with a Titanium alloy probe
CONs
  • Re-calibration may not be so effective

4. HM Digital TDS-4 Pocket-Size TDS Meter

HM Digital TDS-4 Pocket Size TDS Meter

The HM TDS-4 meter is ideal for all water purification applications, wastewater regulation, aquaculture, aquariums, etc. It features ATC (Automatic Temperature Compensation) and advanced microprocessor technology which help tremendously if we talk about TDS meters.

It has a sleek design making the TDS-4 perfect for personal or even commercial use. It it recommended also in the instructions that you turn off and on again the TDS meter, each time before using it.

The package comes with alkaline batteries included.

Hold Function: Locks the measurement you just took to view it outside of the water.
Auto-off function: the TDS meter shuts off automatically after 10 minutes of non-activity.

PROs
  • Inexpensive and pretty accurate TDS meter
  • Easy to handle
  • No temperature nor EC tester
CONs
  • Customer service showed past delays when replacing products

5. HM Digital AquaPro TDS Meter

HM Digital AquaPro TDS Meter

The HM Digital AP-1 TDS meter is an inexpensive and convenient digital tool to instantly check your overall water quality. With the push of a button, the AP-1 can tell you your overall water purity level, which will be displayed on the screen in ppm (parts per million).

The lower the TDS level, the purer the water, with 0 ppm being pure H2O, ideal for a water change in a saltwater aquarium. The AP-1 is great for checking your tap water quality, or knowing when to change a filter.

The AP-1 is a great TDS meter for drinking water,  marine aquariums, RO/DI filtration systems.
Can be safely used to test liquids in temperatures ranging: 0-80 C; 32-176 F.

PROs
  • Measures total dissolved solids (TDS) and temperature
  • Equipped with Automatic Temperature Compensation (ATC)
  • Water resistant housing
  • Digital Calibration with a push of a button
CONs
  • The LCD could have been a little bit bigger for easier readings

6. Lxuemlu Professional 3-in-1 TDS Meter – Best Cheap TDS Meter for Aquarium

Best Cheap
Lxuemlu Professional 3-in-1 TDS Meter

This TDS Lxuemlu meter is ideal for all water purification applications, drinking water, RO/DI water filtration and purification systems, hydroponics (test your nutrients), colloidal silver, aquariums, etc. (The water TDS meter does not check for biological contaminants.)

Although you can’t actually compare it with an expensive laboratory instrument, it is ideal for getting a close estimate of the overall TDS levels.

Whenever it becomes to aquarium TDS water testing, it is an extremely handy device to have around the tank.

PROs
  • One of the best TDS meters for such a low price
  • Awesome customer support
  • Extremely positive reviews from lots of customers
  • 3 in 1 TDS meter
CONs
  • Cheap built and non replaceable battery

7. HM Digital In-Line TDS Monitor – Best Inline TDS Meter for RO/DI systems

HM Digital In-Line TDS Monitor

Although most of the best RO/DI systems available on the market come with an in-line TDS meter included, that’s not a general rule. In this sense, we find the HM Digital DM-1 TDS meter a great choice as an in-line TDS meter for your RO/DI system. Like this, you will easily test the intake and the outtake water TDS levels.

With a quick and easy installation, this TDS in line monitor is highly efficient and accurate due to its advanced microprocessor technology.

Its built in auto-off function conserves battery power shutting off the unit automatically after 10 minutes of non use.

PROs
  • Quick and easy installation
  • Batteries, two sensors and two 1/4″ quick-connect T-fittings included
  • In line TDS monitor for RO/DI systems
  • Durable, operating very well for years
CONs
  • Cannot mention any

8. iSpring 3-Button Digital TDS Meter

iSpring 3-Button Digital TDS Meter

Despite the unbelievably low price, the iSpring TDS meter is accurate, easy to use and highly efficient due to its advanced microprocessor technology.

The TDS reading will be displayed on the LED screen in ppm (parts per million).

The TEMP button naturally display temperature of your reef tank water.

The HOLD button locks and records readings, while the auto-off function shuts the meter off automatically after a few minutes of inactivity.

With a sturdy plastic housing, it is a lightweight TDS meter (1.76 oz) and includes a carrying case with a belt clip for easy portability to any indoor or outdoor water testing.

A trustworthy multifunctional TDS pen to know TDS and temperatures of water in any home, workplace, lab, aquarium, or industrial environment.

PROs
  • Very low price and apparently does a good job
  • 30 days money back guarantee
  • Decent display for the TDS readings
CONs
  • Customers reported inaccurate tap water TDS levels measured

9. Hofun TDS Digital Water Test Meter

Hofun TDS Digital Water Test Meter

The Hofun 3 in 1 digital TDS, temperature & conductivity meter features the most advanced and updated technologies.

Three different measurements can be easily fulfilled by one digital water quality tester in no time. Equipped with premium quality titanium alloy probe, Hofun TDS water quality test meter enables quick and convenient test.

Put the probe into water and the LCD will show accurate results in seconds.

In addition, advanced and reliable Automatic Temperature Compensation (ATC) ensures measurement accuracy, 0-9999 ppm, making it fits multiple usages, hydroponics meter, ideal water testers for drinking water test, saltwater aquariums, RO/DI water filtration systems, etc.

The Hofun TDS meter allows wider angles of data reading and night reading: red backlight (ppm over 40), while the green backlight (ppm below 40).

PROs
  • Easy to read 3 in 1 TDS meter
  • Red readings for ppm over 40
  • Green readings for ppm below 40
  • Wide and clear display
  • Very cheap
CONs
  • Some inaccurate measurements have been reported
  • Re-calibration is not possible

10. Pancellent TDS, PH, EC & Temp 4 in 1 Set

Pancellent TDS, PH, EC & Temp 4 in 1 Set

While for this same price, you can only purchase a TDS meter from other manufacturers, Pancellent provides a nice pack of a TDS, PH, EC and Temperature 4 in 1 set (2 independent pens though).

Within 5 seconds you will be able to know water quality in terms of TDS levels.

The pH resolution is 0.01pH, accuracy ±0.05 pH, TDS: 0~9990 ppm, conducitivity: 0~9990 us/cm, accuracy: ±2%.

The pH pen comes with an auto calibration function, so you shouldn’t need any kind of screwdrivers to calibrate the pH pen tester. This TDS pen has lock and auto shut off functions as well.

PROs
  • 4 in 1 TDS, EC, pH, Temperature meters for a very low price
  • Auto calibration pH meter
  • 6 calibration packs included
  • 30 days money back guarantee
CONs
  • Flaky instructions for the pH meter

Frequently asked questions

What is an acceptable TDS level for reef tanks?

The water that will be used for the reef tank should have TDS values between 0-10. The lower, the better as in the tank itself, the TDS values will increase anyways because of the bioload.

The materials coming out of your tap water comprise organic waste and metals and you don’t want that in your tank.

What does TDS mean and what are its comprised substances?

TDS (Total dissolved solids) = GH + KH + Nitrate + Nitrite + Chlorine + Other Molecular Compounds

What are the optimal TDS levels for African Cichlids tanks?

African Cichlids should ideally live in waters of TDS values between 300-400 ppm. The water parameters can be outside that interval but not too much, and what’s more important is to try and keep constant water parameters for your fish with each water change.

What are general tips to find the proper TDS values?

The desired level of nitrites and nitrates alike is zero for both fresh and marine aquariums. Although a nitrate level of less than 40 ppm is acceptable.

Chlorine is naturally desired to be 0 ppm.

GH (general hardness) is the combination of calcium and magnesium ions found in water. Desired GH will depend on the fish kept in your aquarium.

The KH is typically between 120 and 180 ppm for freshwater and 180-300 ppm for saltwater.

To conclude

Technology has changed now and measuring the TDS water levels for your saltwater tanks has never been easier. With this blog post related to the best TDS meter for aquarium, we hope we were of help in your search for a TDS meter.

To recap shortly, some TDS meters can be hanged on the tank itself, some can be installed in and out of a RO/DI water filtration system (also called in-line TDS meters), while most TDS meters come in the shape of a pen, which is very convenient to use.

Some TDS meters allow re-calibration, which can be extremely useful in case the meter you purchased seems to be inaccurate while measuring water TDS levels. In addition, the advanced and reliable Automatic Temperature Compensation (ATC) ensures measurement accuracy when it comes to the best TDS meter for aquarium. So that’s also something essential to keep in mind.