PPM help

[Hillbilly420]

I have a 3gal dwc going on with led, I have a baby veg in it and she showed some signs of stress, so I moved her from 24/0 to 18/6 well when I got up this morning my ph was the same but my ppm keeps going down to the 130 and back up to 420-430 I use frozen water bottles to keep my water cool, I also don't know what to do when I get root :-\
I was wondering why is the ppm keeps going from 400 range to the 130 range, I'm using a 6 in one meter it tells all I've also calibrated it, thanks y'all

 

[Hillbilly420]

Help

 

[mokel]

heya
is there any water movement which might get air bubbles to interfere with your readings ? if so, unplug any pump/air stone for the time you check and get rid of every single air bubble that might has itself attached to the probe before as well.

about your temps, there are several possible attempts to prevent rot.
1. low temperature (~20°C/68F) and high oxygen saturation in the water
2. adding h2o2 to sterilize it on regular base
3. adding beneficial bacillus and fungi ... hydroguard, (heisenberg) tea, voodoo juice ... see this thread for further information


edit:
i'm not so sure about water bottles in the dwc itself, dunno if you have an external res attached ... those bottles might freeze roots that are in contact with them which would be bad as well

 

[Hillbilly420]

Lol I forgot about the air bubbles I'm waiting to get the rest of my nutes before I change my water I got a 2 1/2 week baby, she was stressing I've changed water already cause I was using tap water and the ph was going insane so I went and got purified water and the ph straighten right out, now last night was the first night it went 18/6 one leaf from the first set is still drawn downward any suggestions?

 

[Hillbilly420]

I don't have any other res besides the one 3 gal u think I could use ice packs or something?

 

[go4snypr]

the ppm should also change based on water/ nutrient uptake of the plant. as the plant gets bigger and you give it more nutes/water the plant will start using it. If the plant uptakes more water than nutes, your ppm will rise and your ph will drop. If your using more nutes than water the ppm will drop and ph will rise. If you check it once and it is 130 and check again without changing your res it should not be jumping up to 450. I would suspect user error. Mokel is probably right with the air bubbles being an issue at this point though.