# Reservoir EC rising as the water level drops: likely causes and fixes

> Reservoir EC rising as the water level drops on cannabis is most often Nutrient burn (feed too strong). How to tell them apart, the fix for each and what recovery looks like.

Also called: ppm going up, EC climbing in res, TDS rising.

Run the checker with this sign: https://genetixbay.com/knowledge/diagnose/?at=roots&s=ec-rising

## Likely causes, most likely first

### Nutrient burn (feed too strong) (Likely)

- Kind: Too much of something; urgency: Low urgency
- Fix: Drop input EC by 0.3-0.5 mS/cm (or to about two-thirds strength); seedlings and clones need 0.4-1.0 mS/cm. Soil with pre-loaded nutrients usually needs plain pH-adjusted water for the first 2-4 weeks. If runoff is far above input, do a root-zone flush (see salt build-up).
- Recovery: No new tip burn on leaves that open after the change, within 5-7 days; burnt tips stay.
- Confirm: Measure runoff EC against input EC: Water to 10-20% runoff, collect the runoff in a clean cup and measure EC of both with a calibrated meter (1.413 mS/cm standard). Runoff more than ~0.5 mS/cm above input means salt build-up; well below input means the plant is hungry or you are over-leaching. In hydro, compare reservoir EC with the EC you mixed.
- Confirm: Pour-through extraction for container pH and EC: Water normally, wait 30 minutes to 2 hours, pour enough pH-adjusted water on top to collect about 50 mL of leachate (roughly 75 mL for a 15 cm pot, 150 mL for a 4 L pot, 350 mL for 11 L), and measure pH and EC of that 50 mL. Less disruptive than full runoff and more repeatable.
- Article: [Brown or burnt leaf tips on cannabis: a differential](https://genetixbay.com/knowledge/diagnosis/brown-burnt-tips.md)

## Note

Guidance, not a guarantee. The checker weighs common causes against what you tell it; confirm with the tests before you treat, change one thing at a time and watch the new growth.