ec and tds

[ineke]

Hi I can't find the good write up about EC and TDS pens so can anyone shed light on my reading.

TDS is 125 ppm and EC 27

TDS 187 EC 41

Two different tanks just for comparison. I'm stumped because I thought the EC should be higher than that.

Never was any good at this type of thing!!!!!:confused-new:

[JohnH]

hmmm, dunno what your EC reading is as this is one of my tanks

EC: 307

TDS: 153

Maybe someone who knows more can help?

[MrShrimp]

One of your pen is incorrect. If your tds is 190, then your EC should be around 400 ish. You need to find which pen is incorrect and calaborate it. I usually use my ro/DI water to check the pen. RO/DI water should have a tds around 3 or under.

[ineke]

Thanks MrShrimp my EC pen came with chinese instructions any idea what the EC for RO water should be?

[ineke]

well TDS pen says RO water from 2 different containers is 5 has been standing for a couple of days in sealed bottles. The ec reads 01 does that mean anything to anyone?

[JohnH]

Maybe it has something to do with EC can be measured by mS/cm or mS/m? Maybe your meter is showing mS/m and mine is mS/cm? If you add a 0 to your EC readings then they would be around what mine are?

I was never much good a maths so I could be totally wrong.

[MrShrimp]

I think your EC pen is out of wack. You need to adjust it. Tds 5 for RO water seems correct.

[ineke]

I think your EC pen is out of wack. You need to adjust it. Tds 5 for RO water seems correct.

Yes I think that is the problem unfortunately the instructions for calibration is in chinese so can't follow it. Have refered back to seller to see if they can send english instructions

Thanks

[ineke]

Maybe it has something to do with EC can be measured by mS/cm or mS/m? Maybe your meter is showing mS/m and mine is mS/cm? If you add a 0 to your EC readings then they would be around what mine are?

I was never much good a maths so I could be totally wrong.

Mine is reading u's/cm I don't have a scientific keyboard with the proper u sign. I think it is short for micro

[ineke]

Peering through the chinese instructions this meter has a notation it is a cd303 (x10) so would that be better if I times the reading by 10 which means you are right John?

[JohnH]

Yep, I reckon that would be it.

[ineke]

Yes I think x10 and it should be near enough I hope!!!

[BlueBolts]

Does the meter actually denotes EC 27 ? Or does it just show a conversion of 27 ? Converting mS/Cm of 27 = 270 (x10)...does seem to be somewhat correct but the converstion should be approx. a factor of 0.5, 0.64 or 0.7, depending on region it is made for... your conversion to CF is 270 which is equates to a factor of 0.46...perhaps close enough to 0.50, but really not sure....

If you RO resin is fresh, TDS of your RO unit should read 0......it creeps up once the resin starts getting exhausted.

EC stands for Electrical Conductivity. Nutrient ions have an electrical charge. EC is a measurement of all those ions that have an electrical charge. The more electrically charged ions in a solution the higher the EC reading.CF stands for Conductivity Factor. This is exactly the same as Electrical Conductivity (EC), but does not have a decimal point in the reading.mS/cm² - millisiemens per cm. 1 mS/cm = 10CF

[ineke]

BB it's all way above my head my RO unit is only about 1 month old the water is about 2-3 days old stored in plastic bottle in the house and all the info for the EC tester is in Chinese . I just know it it a CD303. I will try and get Alan to have a look at it over the week end, he can usually work these things out. I don't think my RO unit membrane can be exhausted yet. Main thing is all WP are stable and shrimp seem ok, plenty of exoskeletons in the tanks, every tank except new one has berried females and I have had no deaths for quite a while. If I need to down the track I will spend the money and buy a decent pen rather than the cheaper ones I have. :encouragement:

[BlueBolts]

Theoritically, RO water will not deteriorate over time, as it has no organic components.... so whether RO water is sitting for 1 -100 days, it's TDS/Ec should remain 0. I have a cheap TDS/Ec (converts automatically) and a expensive TDS pen, and they both work perfectly...just luck of the draw.

Yes, if the shrimps are breeding and happy, then it's all good.