pH issue, need help solving source

[DarkWizard021]

Ok I have a pH issue that has me baffled. I can pH my res to 5.6 and 12 hours later pH will be 6.8 or higher. I can't figure out the cause, and don't want to scrap and start over.

Setup:
50gal roughneck res (10 gal used for water)
Aero/dwc hybrid setup
400w hps/mh
Wire mesh pots 3"

Temps run between 65-80
Humidity 35-48%
12/12 light cycle

This issue did not happen until flowering, it's not looking like it is hurting the plants, but I don't want to "chase" the pH and have to adjust it every day.

Anyone that runs aero or Dwc ever seen this issue?

 

[hondagrower420]

The ph will rise as the plant eats.

Do you have a tds meter?

What buffer are you using?

 

[Mish12345]

Check for root rot make sure u getting loads of aeration to nutes add sum pythoff or just chlorine.. In small amounts

 

[DarkWizard021]

Yea ppm atm is at 1400, clay pebbles for medium

 

[hondagrower420]

Yea ppm atm is at 1400, clay pebbles for medium

What about your buffer and what brand nutes?

 

[BamaBoyBeRolling]

With the temp up to 80 I would use at least a base model commercial grade air pump because those aquarium pumps that come with the dwc buckets don't do it justice.

 

[JohnySmith1]

Hi, impurities on clay pebbles cause pH to rise. Clay pebbles must be washed properly and then soaked in acidic water. What I suggest, take basket with pebbles out of the system and flush it properly with pHed water.

 

[JohnySmith1]

also, reduce the level of your water in the reservoir so it's just slightly below the pebbles