# Acclima TDR-310W

### Rockwool cubes and slabs

For accurate readings, place the probe at the following positions:

* 4” x 4” x 4” cubes → 1 inch above the base
* 6” x 6” x 4” cubes → 1 inch above the base
* 6” x 6” x 6” cubes → 1 inch above the base
* 8” x 8” x 8” cubes → 2 inches above the base
* Rockwool slabs → 1 inch above the base in individual cubes

If using a rockwool slab, position the probe equidistant between two plants to capture the most representative root-zone conditions.

### Coco coir and organic substrates

Probe placement depends on pot size for the most accurate root-zone readings:

* 1-gallon coco pots → 1 inch above the base
* 2-gallon coco pots → 2 inches above the base
* 3-gallon and larger coco pots → 3 inches above the base

#### Large no-till or living soil beds

Check out our FAQ for this specific use case below.

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[how-do-i-position-my-substrate-probe-in-a-large-no-till-or-living-soil-bed](https://faq.growsensor.co/substrate-probes/how-do-i-position-my-substrate-probe-in-a-large-no-till-or-living-soil-bed)
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