Making sense of PPM/pH changes

[Nate_in_AK]

My light and humidifier are on the same timer circuit. Both go off at midnight, come back on at 6AM.
During the day temp ranges from 70-75F, with humidity around 60%.

Check res last night: 650PPM, 5.8pH

Check res at 9AM: 350PPM, 6.2pH
Check res at 11:30AM: 450PPM, 6.0pH
Check res at 1:30PM: 700PPM, 5.9pH

Water level change between 1:30PM today and yesterday approx. 1 gallon down.

This suggests to me the plants are eating at night (PPM drop), and drinking during the day (PPM rise).

Is that "normal"??

 

[Marzcanna]

Hi, Are you growing in soil or coco? This only happens to me in coco. As you said your plants are eating what they need and the rest is becoming salt buildup thats why your ppm/EC go up. Do an experiment and dont feed them for a day or two, if the PPM goes down than your plants are eating and maybe lower feeding PPM slightly

 

[PpmOver9000]

sounds like dwc since he is referencing his water level.

 

[Marzcanna]

I don't have much experience with DWC but id say lower your feeding strength abit

 

[Kampbe1l]

photos....

 

[N1ghtL1ght]

It's normal that plants need more water during lights on as more than 90% of that is just used to cool the leaves via evaporation.

 

[Nate_in_AK]

It's normal that plants need more water during lights on as more than 90% of that is just used to cool the leaves via evaporation.

Hmm, that's interesting. I feel like that should have occurred to me. Thanks!