Measuring TDS in runoff

Hey all,

I’m growing indoor, using promix and Advanced Nutrients PH Perfect nutes.

I’ve been testing the runoff water and keep note of the results.

I’m watering each plant with 6L every 4 days. I’m using 20L (5g) pots, but they are about 2/3 full, using promix HP as medium.

Going in, the water has a PH of about 5.9 with a TDS of 860 to 910ppm.

When I test the runoff water, so far it ranges from 110 to 150ppm and PH of 5.95 to 6.10.

The plants seem otherwise healthy. I’m just finishing week 10 of veg.

Can anyone help me with interpreting these results?


That means the nutrient density of your medium is pretty low and absorbed most of the nutrients you gave it before passing through essentially filtered water you probably need to up it a bit since it sounds like your girls are drinking more then your giving

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What @GreenSnek said, they are hungry. Runoff PH is good and seldom are the input and runoff the same

Thank you guys !

I’m gonna try to increase the frequency of the watering.