Taking the confusion out of TDS and Hydroponics

Hey!

You are most likely here because You are looking for extra information and instructions on how to use Your TDS Meter, what different results mean and get Your most common questions answered.

You can claim the General Ebook Below. If you are a Hydroponics user, scroll down further to the second download.

 

FOR HYDROPONICS GROWERS: Taking the confusion out of TDS and hydroponics...

Hydroponic growers know the importance of managing their nutrient solution strength from seedlings to harvest. They love the Health Metric TDS meter but are often confused about the science behind TDS, EC (electrical conductivity) and conversion factors. We like to refer growers to expert information so they get the best and most accurate answers. Unfortunately, a lot of the technical information on TDS meters is way too complicated for the grower who just wants to manage the nutrient solution. A lot of the message boards “got it wrong” and only add to the confusion! 

The more growers searched and read, the harder it became to get to the facts. A lot of you guys were getting really stressed about your nutrients. We decided to write out own little manual to explain the relationship between TDS, EC conversion factors and the Health Metric TDS meter. The whole thing is based on the questions we receive from growers about the subject. The TDS questions were similar but often mixed up by “what the internet said” was correct. Just so you know, we didn’t just copy it from a website. This is the “recipe” we used to write the TDS manual.

  • 30 years of water chemistry experience
  • 20 years of hydroponics experience
  • 5,000 answered questions about water, TDS and other growing factors
  • Ability to make science simple and easy to use

If you’re ready to finally understand how TDS meters work and what it all means to hydroponics. Enter Your E-mail Below. It won’t hurt your head! We promise.

 

  • Do you have koi ponds or water gardens?

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    Read our blog post about understanding TDS in koi ponds and water gardens. 

     

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    TDS Meter FAQ

    TDS meters work by measuring the electrical conductivity (EC) of the water. Substances that have conductivity, like calcium, sodium, chloride, potassium, etc will all add to the conductivity of the water. Things that don't conduct a current (like sugar) won't register a current. The meter uses the EC to calculate a general TDS measurement. The true scientific method would be to evaporate the water and measure what is left behind. This method requires a lab. But since it works by weighing what is left after the water leaves, it DOES include substances like sugar and tannins from a peat bog, etc. But for drinking water you're not going to find sugar and brown peat tannins coming from the tap. So..all TDS meters are EC meters, even if they don't indicate it on the display. EC is converted to TDS and shown on the display. Hydroponic growers are really into EC for nutrient calculations. TDS meters don't know what they are reading. A high TDS (400) is not ""poison"" or harmful. In 99% of cases it just means there are a lot of minerals in the water. Bottled mineral water will often have a high reading like this too. Reverse osmosis and distilled water will have 0-10 TDS. Bottled drinking water, spring water and ""filtered water"" can be all over the TDS map depending on the source of the spring or tap water supply. Unless you are using a filter that removes a lot of salts and minerals, you won't see much of a decrease in TDS after passing it through a normal water filter. Reverse osmosis, deionization and distilling remove TDS. A water softener, carbon filtration and particulate filters do not remove TDS in any measurable way in most cases. They do take care of other issues, however. You can get a general idea if a water sample is going to taste good or have a lot of minerals that can cause off-flavor with TDS. If it gets around 450 and above, the water will probably taste bad. Maybe bitter or even metallic. Your water filter will eliminate chlorine, most tastes and odors and some heavy metals, pesticides and chemicals...so you should be fine if you are using a modern water source. You can get a general idea if a water sample is going to taste good or have a lot of minerals that can cause off-flavor with TDS. If it gets around 450 and above, the water will probably taste bad. Maybe bitter or even metallic. Your water filter will eliminate chlorine, most tastes and odors and some heavy metals, pesticides and chemicals...so you should be fine if you are using a modern water source.
    The difference lies in microsiemens vs millisiemens. The meter is measuring EC in milli and the level you are comparing it to in micro. There is a 1000x difference. I have attached our guide that describes everything in easy to read detail. Basically, if you want to compare apples to apples as they say... 1.6 millisiemens = 1,600 microsiemens, which is the scale the EC meter is using. 664 us/cm = 664/1000 = 0.664 millisiemens. You can usually tell which scale people are refering to by the decimal. If there is a low number with a decimal...it is milli.
    No. A TDS meter cannot tell you the water hardness level. It detects all dissolved minerals and salts(TDS) and provides the TDS level in ppm.
    Sometimes Amazon doesn't send our attached files through. Please scroll up on this page and see the section where you can download it.
    It is difficult to measure a salt concentration with a TDS meter. TDS meters use the electrical conductivity of all ions to come up with a TDS measurement. This makes it very difficult or impossible to get a salt measurement. The meter is measuring water hardness, alkalinity from pH buffers, water treatment chemicals and other substances including salt. Some pool owners test the TDS of the water they use to top off the pool. This is baseline TDS. Then they test the pool. You can subtract the baseline from the pool TDS to get an idea of the salt level minus most of the other substances in the pool. Add enough salt to get in the middle to upper end of the suggested salt range and you should be right in the salt zone.
    Yes. The meter can be used in EC or TDS mode for hydroponics.
    That is because most water filters do not remove salts and minerals.
    Yes. A TDS reduction of 70-100% means the membrane is working properly.
    EC Mode tests for Electrical Conductivity. TDS meters use EC to calculate the TDS level.
    No. The meter has two probes.
    It must be defective from the factory. Please send your Amazon order number to us at: [email protected] and we will replace it immediately.
    Got a question that is not listed? Email us at: [email protected]
    We are here to help.