xxedgexx
Active Member
I'm a new grower. Only on my third round. Honestly, things haven't gone so well, but I might have just discovered why.
I don't know why I never read this. I had nothing to compare it to I guess.
Here's what happened:
So I just figured out a major mistake I made, but learned something new. Turns out I was calibrating my ppm meter using the NaCl scale. The meter uses "442
scale", so basically my ppm's were about 610 ppm's higher then what the meter was saying. Shit...now that I know this, it's obviously something I've been
miscalculating from the beginning and probably explains a lot of my issues. I had no idea about these different scales. The only reason I figured this out
is because I went out and bought a fairly expensive meter, to try and avoid any inaccurate readings. Things didn't add up on this new ppm meter which was
calibrated at the factory and actually signed off by a human. I checked the calibration using the solution I had and things were way off. It didn't make
sense. This is a $275 meter.
Then I found this web site:
http://www.hydroponics.net/learn/debate_over_ec_and_tds.asp
The Hanna calibration solutions that came with the meter used the scale Hanna instruments is used to, so the readings between my old meter and my new meter
were way off.
I now calibrated my old meter using the correct scale and the new meter and old meter now read almost exactly the same. I calibrated the new meter using EC
rather then TDS and now TDS matches on both meters. This is how I know that I was using the wrong scale completely.
Anyway, this explains a lot. Fuck.
So my ppms were actually somewhere around the 1800 - 1900 range. Ouch. I pumped about half the water out of my res and I'm refilling with fresh water to
bring the ppms down to somewhere around 1000. Does this make sense? First week of veg, using AN nutes and Botanicare Sweet. Do you think I would be better off completely flushing my res?
I hope it's not too late and I didn't send the plants into shock. What do you think?
I don't know why I never read this. I had nothing to compare it to I guess.
Here's what happened:
So I just figured out a major mistake I made, but learned something new. Turns out I was calibrating my ppm meter using the NaCl scale. The meter uses "442
scale", so basically my ppm's were about 610 ppm's higher then what the meter was saying. Shit...now that I know this, it's obviously something I've been
miscalculating from the beginning and probably explains a lot of my issues. I had no idea about these different scales. The only reason I figured this out
is because I went out and bought a fairly expensive meter, to try and avoid any inaccurate readings. Things didn't add up on this new ppm meter which was
calibrated at the factory and actually signed off by a human. I checked the calibration using the solution I had and things were way off. It didn't make
sense. This is a $275 meter.
Then I found this web site:
http://www.hydroponics.net/learn/debate_over_ec_and_tds.asp
The Hanna calibration solutions that came with the meter used the scale Hanna instruments is used to, so the readings between my old meter and my new meter
were way off.
I now calibrated my old meter using the correct scale and the new meter and old meter now read almost exactly the same. I calibrated the new meter using EC
rather then TDS and now TDS matches on both meters. This is how I know that I was using the wrong scale completely.
Anyway, this explains a lot. Fuck.
So my ppms were actually somewhere around the 1800 - 1900 range. Ouch. I pumped about half the water out of my res and I'm refilling with fresh water to
bring the ppms down to somewhere around 1000. Does this make sense? First week of veg, using AN nutes and Botanicare Sweet. Do you think I would be better off completely flushing my res?
I hope it's not too late and I didn't send the plants into shock. What do you think?
