30MHz has multiple calibrations provided in the platform. Click here to find out how to set the calibration for your sensor in the platform after choosing the calibration that suits best for your substrate.

In this article:
Calibrations provided by Metergroup
        - Mineral
        - Soilless
Calibrations provided by 30MHz
        - Organic type grow media
        - Stone wool type starter blocks
        - Stone wool type grow media
        - Perlite type grow media
How to choose the calibration that fits your substrate?

Calibrations provided by Metergroup

There are two generic calibrations provided by Metergroup, mineral and soilless. According to Metergroup, the generic calibrations should result in an absolute accuracy from 1% to 3% VWC for most mineral soils up to 8 dS/m EC saturation extract, and 5% for soilless media like potting soil, perlite, and peat.

 

Mineral

The generic calibration profile mineral is made by Metergroup to serve customers who use natural mineral soil types. The highest sensor readout, whilst using this profile, is 60% VWC. This is due to the behaviour of soil and water, where the total volume of water in a saturated situation will not be higher than this. Therefore a test in a bucket of water will never read 100%, which is true for all calibrations by 30MHz and Metergroup.

 

Soilless

Besides Mineral, Metergroup offers a soilless calibration for potting soil, perlite, and peat. The differences between mineral soil and soilless media calibrations are caused by organic soils having a higher air volume. For Soilless the maximum measured VWC is 85%. This is due to the behaviour of substrate and water, where the total volume of water in a saturated situation will not be higher than this.

 

Calibrations provided by 30MHz

30MHz supports the following calibrations described below. These calibrations are executed on a specific soil sample and EC value by Metergroup. We can calibrate your substrate if the calibration is not available already. Please get in touch with us to be informed about the calibration options and pricing.

Below you will find the following available calibrations:
Organic type grow media
Stone wool type starter blocks
Stone wool type grow media
Perlite type grow media

The maximum VWC percentage is below 100% for every calibration as the sensor always takes the volume of soil/substrate into account.

The calibration profiles are divided into EC aim value and insertion type. Please make sure that you insert the sensor in the substrate as the calibration profile describes.

 

The calibration naming is build up as follows:

 

Organic type grow media

For organic type grow media we have calibrations for Agaris, Botanicoir PPU, Botanicoir Dry, Botanicoir Dry XD, Forteco, and Coir universal. Per calibration, you can find the right profile per position of the sensor in the slab listed below.

 

Agaris - (natural organic materials based)

2cm-bottom

4cm-bottom

6cm-bottom

 

botanicoir_PPU - (coir (cocos) based)

botanicoir_dry - (coir (cocos) based)

botanicoir_dryXD - (coir (cocos) based)

2cm-bottom

4cm-bottom

6cm-bottom

Forteco_profit - (coir (cocos) based)

6cm-bottom

4cm-bottom

coir_universal_B - (coir (cocos) based)

2cm-bottom

4cm-bottom

6cm-bottom

Stone wool type starter blocks

For stone wool type starter blocks we have calibrations for grodan plantop and hollandplant. Per calibration, you can find the right profile per position of the sensor in the slab listed below.

grodan_plantop

2.8dS, 3.0dS, 4.0dS, 7.0dS and 11dS

top (most convenient)

side (most precise) (equivalent to middle insert of the image)


hollandplant

1 hole or 3 hole variant

side (equivalent to middle insert of the image)

top

Stone wool type grow media

For stone wool type grow media we have calibrations for Cultilene Reaxxion, Grodan GT Expert, Grodan Prestige, Grodan GT Master and Grodan Vital. Per calibration, you can find the right profile per position of the sensor in the slab listed below.

 

cultilene_reaxxion

2.5ds and 3.75ds

top

top_third

middle

lower_third

grodan_gt_expert

side-middle,

bottom-middle,

 

grodan_prestige

20x8 in combination with 2.8dS

10x15 in combination with 4.0ds

10x15 in combination with 2.8ds

middle

bottom

grodan_gt_master

1.5dS or 5.0dS

top_third

middle

bottom_third

grodan_vital

1.5ds or 5.0dS

top

top_third

middle

bottom_third

 

Perlite type grow media

For perlite type grow media we have calibrations for Hollandplant Perlite, Pull Rhenen and Willems Perlite Opkweekblok F1. Per calibration, you can find the right profile per position of the sensor in the slab listed below.

 

hollandplant_perlite

1-3b

side

pull_rhenen

100_55

90_59

80_49

willems_perlite_opweekblok_f1

1-3b

side

How to choose the calibration that fits your needs

In the platform, you can set the calibration per sensor. Now that you have seen the available calibrations, you might want to decide which calibration you should use. See the image below to decide in a few steps which calibration is the best match for your substrate. Download the image below the article for a larger image.