  We discuss magnetically ordered ("superfluid") phase near quantum transition
to Bose-glass phase in a simple modeling system, Heisenberg antiferromagnet in
spatial dimension $d>2$ in external magnetic field with disorder in exchange
coupling constants. Our analytical consideration is based on hydrodynamic
description of long-wavelength excitations. Results obtained are valid in the
entire critical region near the quantum critical point (QCP) allowing to
describe a possible crossover from one critical behavior to another. We
demonstrate that the system behaves in full agreement with predictions by
Fisher et al.\ (Phys.\ Rev.\ B {\bf 40}, 546 (1989)) in close vicinity of QCP.
We find as an extension to that analysis that the anomalous dimension
$\eta=2-d$ and $\beta=\nu d/2$, where $\beta$ and $\nu$ are critical exponents
of the order parameter and the correlation length, respectively. The density of
states per spin of low-energy localized excitations are found to be independent
of $d$ ("superuniversal"). We show that many recent experimental and numerical
results obtained in various 3D systems can be described by our formulas using
percolation critical exponents. Then, it is a possibility that a percolation
critical regime arises in the ordered phase in some 3D systems not very close
to QCP.
