# Are EC meters and TDS meters the same thing?

Discussion in 'Hydroponic Growing' started by Mashiro, Mar 13, 2012.

1. I'm very confused about how to measure the nutrients in hydroponic water.

What's the difference between the two different kinds of meters?

Pros and cons of each one?

Also, a plus if you can link me an affordable combo meter to test Ph and PPM.

2. Tds is total disolved solids and is measured in ec or electrical conductivity and ppms is just a conversion of ec, so in short, yes they are the same thing.

3. Hey Mashiro just a thought on pens
I'm a butterfingers because of arthritis my pens float because i drop stuff...cost a little more but worth it.

4. Yeah, they all have different meanings/scales... but you can only really measure EC easily, then use science/math to approximate what ever else.

Electrical Conductivity (ec) is... the electrical conductivity of the water. Pure H20 is not conductive, the charge is carried by the dissolved ions in water. So the more stuff in the water the more conductive it is. This is what is measured.

PPM is parts per million, a measurement of how many parts of solute are in the water per million parts of water. This is calculated based off how conductive the water is.

Total dissolved solids is a measure of how much dissolved solid there is per mass in a certain volume of water.

You can see EC is basically the actually measurement most often took to calculate one of the other two. It is just different ways of expressing purity.

5. Thanks guys!

6. Here is a calculator to convert between ppm @ 0.5, ppm @ 0.7, EC/mS and EC/uS

CannaStats - Cal-O-Rama

(at the bottom of the page)

Also, a great ppm @ 0.5 conversion meter is the HM EZ-TDS, it's very accurate and only \$16. Got tons of great reviews on amazon