Sunburn or decease?

[Dorsetman]

Water quality.

I really cannot understand why so many folk quote TDS figures. TDS is hooey, pseudoscience.

Quote ; The only way of accurately measuring the TDS of a nutrient solution is to evaporate all the liquid and measure the residue - this would kind of defeat the point ! ; unquote.

What TDS meters actually do is measure the Electrical Conductivity or EC, and then convert it.
There are two problems with conversion. (1) the conversion scale is non-linear, ( at different temperatures) and (2) there are at least 4 different conversion scales in use.

In practice, here are the conversion figures for a number of popular TDS meters :-

Truncheon - 0.7
Guardian - 0.5
Hanna HI 98301 - 0.5
Hanna 98140 - 0.7
EcoTester - adjustable between 0.4 and 1.0

In other words, your TDS 200 may be my TDS 300 or maybe it is my 150….and so on. So it is meaningless flor a guide unless you also quote your TDS model, and I go out and find the same model.

So why not use EC ? That is always the same - your EC is the same as my EC ( if we are dipping our meters into the same bucket of solution ) whatever meters we use. It is an electrical current measurement - whatever the temperature and whatever the meter.

And if you want to know what EC to use - I have measured this in the collected drips from the roots of epiphytic orchids in rain storms in the growing season in the jungle on more than one occasion, and found it to be in the range 450-650 EC - which are the figures I use ( according to genera).

Make sense , does it not ?

I have been saying this, in forums like this , for years, and still it goes on….

[Ana Danaya]

Water quality.

I really cannot understand why so many folk quote TDS figures. TDS is hooey, pseudoscience.

Quote ; The only way of accurately measuring the TDS of a nutrient solution is to evaporate all the liquid and measure the residue - this would kind of defeat the point ! ; unquote.

What TDS meters actually do is measure the Electrical Conductivity or EC, and then convert it.
There are two problems with conversion. (1) the conversion scale is non-linear, ( at different temperatures) and (2) there are at least 4 different conversion scales in use.

In practice, here are the conversion figures for a number of popular TDS meters :-

Truncheon - 0.7
Guardian - 0.5
Hanna HI 98301 - 0.5
Hanna 98140 - 0.7
EcoTester - adjustable between 0.4 and 1.0

In other words, your TDS 200 may be my TDS 300 or maybe it is my 150….and so on. So it is meaningless flor a guide unless you also quote your TDS model, and I go out and find the same model.

So why not use EC ? That is always the same - your EC is the same as my EC ( if we are dipping our meters into the same bucket of solution ) whatever meters we use. It is an electrical current measurement - whatever the temperature and whatever the meter.

And if you want to know what EC to use - I have measured this in the collected drips from the roots of epiphytic orchids in rain storms in the growing season in the jungle on more than one occasion, and found it to be in the range 450-650 EC - which are the figures I use ( according to genera).

Make sense , does it not ?

I have been saying this, in forums like this , for years, and still it goes on….

Hi Geoff
Good morning. It actually makes sense
What is the EC you use for Catt?
I will get myself an EC meter

[ksriramkumar]

Good one Geoff. Hatsoff to you. Got to love your wisdom. Wishing many more years of good health Geoff.

Water quality.

I really cannot understand why so many folk quote TDS figures. TDS is hooey, pseudoscience.

Quote ; The only way of accurately measuring the TDS of a nutrient solution is to evaporate all the liquid and measure the residue - this would kind of defeat the point ! ; unquote.

What TDS meters actually do is measure the Electrical Conductivity or EC, and then convert it.
There are two problems with conversion. (1) the conversion scale is non-linear, ( at different temperatures) and (2) there are at least 4 different conversion scales in use.

In practice, here are the conversion figures for a number of popular TDS meters :-

Truncheon - 0.7
Guardian - 0.5
Hanna HI 98301 - 0.5
Hanna 98140 - 0.7
EcoTester - adjustable between 0.4 and 1.0

In other words, your TDS 200 may be my TDS 300 or maybe it is my 150….and so on. So it is meaningless flor a guide unless you also quote your TDS model, and I go out and find the same model.

So why not use EC ? That is always the same - your EC is the same as my EC ( if we are dipping our meters into the same bucket of solution ) whatever meters we use. It is an electrical current measurement - whatever the temperature and whatever the meter.

And if you want to know what EC to use - I have measured this in the collected drips from the roots of epiphytic orchids in rain storms in the growing season in the jungle on more than one occasion, and found it to be in the range 450-650 EC - which are the figures I use ( according to genera).

Make sense , does it not ?

I have been saying this, in forums like this , for years, and still it goes on….