Variable TDS readings.

[Hectorsgaf]

Hi. As a beginner with these I now have 7 starter plants from reputable suppliers.  They are in water in a black standard plastic plant tray in the garden. They look good.  My issue is, having done the research, the water.  I have collected rain water in the trays. The water that runs into my barrels comes off an asbestos garage roof and is around 150tds.  I do not use it.  So I collect direct into trays.  The readings in here were around 30 so all good.  We had rain again last night but the tds is now showing 85.  I do not want to get paranoid about this but why would the level have gone up like this?  Is it different rain?  I cannot imagine plant tray leaches solids into the rain water that quick.   Advice appreciated.  Thank you

[Tropfrog]

I think this is an issue of false readings due too bad measuring equipment or just pourly calibrated. I think rain water is ok no matter from your roof or from the tray.

I have never measured TDS and my plants are ok.

Br

Magnus 

Edited September 9, 2022 by Tropfrog

[Hectorsgaf]

2 minutes ago, Tropfrog said:

I think this is an issue of false readings due too bad measuring equipment. I think rain water is ok no matter from your roof or from the tray.

I have never measured TDS and my plants are ok.

Br

Magnus 

I have 2 test meters and they do vary against each other.  I appreciate that cheap instruments will vary greatly in accuracy.  However, notwithstanding the margins they both now show a distinct increase in the rainwater collected over night.  They are not totally inaccurate though as I also use de ionised water and and distilled water as a base test.   These show 0.1 and 0.0 respectively.    The rain water from the roof is clearly much higher in tds than the water collected in the plant tray direct from the sky.  It is the way the latter has increased with standing time over 24 hours that puzzles me when in a n inert plant tray.