Lucas add back calculate question

[stickywicked]

Question 1:my tads meter is off by 54 ppm and my tap water reads at 156, that's 210 ppm that must be added to any reading I take. My reservoir reading was 573, plus 210= 783. After I work the Lucas add back calculate I need to add 56ppm to be at target ppm. When should I worry about it? Am I doing this right?

 

[Flyinghigh]

I would say get another ppm pen.

 

[7greeneyes]

:smoke1:

 

[The Hemp Goddess]

I never add back to nute solutions. Plants do not uptake nutrients evenly, so you really never know what is in the remaining solution in the res. I believe that it is best to change out your res every 7-10 days.

How do you know your ppm meter is off 54 ppm?

 

[stickywicked]

Used test solution

 

[LEFTHAND]

Used test solution

Can you not calibrate your meter. ???
You should be able too.
LH.

 

[stickywicked]

It s a cheap one. Don t think its possible. But by adding in the Ppms from my tap water and the test solution difference, I hope I'm doing this right, it s a 210 ppm difference. The pen consistory reads the same in the test solution.