The Utah Hydroponics solutions were developed using mass balance principles coupled with tissue analysis from studies in 25-cm deep, continuously aerated, liquid hydroponics. Because there is no solid phase (soil-less media) in liquid hydroponics, there is no absorption or desorption with media.
These solutions provide guidelines, but are not necessarily appropriate for use with soilless media where cation exchange capacity and thus absorption and desorption with the media can be significant.
Bugbee, Bruce and Langenfeld, Noah, "Utah Monocot/Dicot Solution" (2021). Nutrients. Paper 2.