DWC - Sharp overnight fall in PH ? -

18 gal rez using 15 gal. over 30 LPM of air bubbling, 1000w HPS, plenty of airflow. Inside the rez is advance nutrients jungle juice grow at 750ppm with beneficial ewc/hydroguard/greatwhite tea. PH fell from 5.7 to 4.3 overnight and do not know why. Disease shouldn’t be a problem because of the tea, why else would pH drop? Ppm also went up from 850 to 860 that same night so i diluted to 750 ppm. Any ideas? plants look great and roots are coming back from minor root rot

Reservoir temperature and air temperature ranges?


@MacGyverStoner 66-71 F, air temp 70-82 F

I don’t know about the brand of nutrients, but your parameters seem in check, Something seemsis very wrong though. Your leaves and leaf stems are screaming nutrient deficiencies!

The ppm rising is very worrisome, this usually seems to be a symptom of root rot in a DWC.

I’m guessing most of this is probably from the root rot. If things are coming back, it should continue to improve and you are just going to have to help her along.

Happy growing,


1 Like

Thanks fr the response, I’m going to switch to pH perfect nutrients to help reduce the swing. Can I ask what you see in the leaves/stems that scream deficiency? @MacGyverStoner

The red/purple stems and the speckles in the leaves. The spots on the leaves won’t go away as the plant gets better, but the red stems should diminish or lessen and the new leaf growth should not have spots, indicating things are on the mend.

If the red stems stays or gets worse, and the new growth also has freckle like spots, then things are not really getting better. The spots and red stems would normally be an indicator of a potassium deficiency, but it is likely due to the conditions of the root rot and then the plant couldn’t uptake the potassium, rather than there not being enough in the nutrient mix or reservoir.


1 Like

I use General Hydroponics grow and then bloom and had issues with pH dropping as well. Started adding GH Armour Si and that has solved the issue for me.