Testing tap EC for soil

[CBDictonary]

Ok so testing 1ml shogun CalMag in 1L of water gives an EC reading of 0.5

Spoke to the shop who said it was calibrated, and suggested until I can get hold of calibration fluid I test with some mineral water...

Mineral water read EC 0.4

So very possibly the water is EC 0.0 here?

With this in mind would you be adding calmag from first feed?

Thanks for any insights!

 

[bad dragon bzzz]

All pens are caIibrated out the factory,after a trip in the back of a van,getting thrown around by post people,imo all pens should be recalibrated before first use.
A ppm/ec/tds/ph without fluids is as usfull as a ruler with no lines or numbers.(a stick)use biobizz nutes and soil.i start feeding about day 10.my tap water is 160 ppm not sure what that is in ec.as your ice water could have zero cal/mag i think adding calmag would benefit.