For details on the choice of the balances, please, see at the research report for which the link is given below.
References
Egozcue J.J., V. Pawlowsky-Glahn, G. Mateu-Figueras and
C. Barcel'o-Vidal (2003) Isometric logratio transformations for
compositional data analysis. Mathematical Geology, 35(3)
279-300 \
Hron, K. and Templ, M. and Filzmoser, P. (2010) Imputation of missing values for compositional data using classical and robust methods
Computational Statistics and Data Analysis, vol 54 (12), pages 3095-3107.