  We explore the circumgalactic metal content traced by commonly observed low
ion absorbers, including C II, Si II, Si III, Si IV, and Mg II. We use a set of
cosmological hydrodynamical zoom simulations run with the EAGLE model and
including a non-equilibrium ionization and cooling module that follows 136
ions. The simulations of z~0.2 L* (M_200=10^11.7-10^12.3 Msol) haloes hosting
star-forming galaxies and group-sized (M_200=10^12.7-10^13.3 Msol) haloes
hosting mainly passive galaxies reproduce key trends observed by the COS-Halos
survey-- low ion column densities show 1) little dependence on galaxy specific
star formation rate, 2) a patchy covering fraction indicative of 10^4 K clouds
with a small volume filling factor, and 3) a declining covering fraction as
impact parameter increases from 20-160 kpc. Simulated Si II, Si III, Si IV, C
II, and C III column densities show good agreement with observations, while Mg
II is under-predicted. Low ions trace a significant metal reservoir, ~10^8
Msol, residing primarily at 10-100 kpc from star-forming and passive central
galaxies. These clouds tend to flow inwards and most will accrete onto the
central galaxy within the next several Gyr, while a small fraction are
entrained in strong outflows. A two-phase structure describes the inner CGM
(<0.5 R_200) with low-ion metal clouds surrounded by a hot, ambient medium.
This cool phase is separate from the O VI observed by COS-Halos, which arises
from the outer CGM (>0.5 R_200) tracing virial temperature gas around L*
galaxies. Physical parameters derived from standard photo-ionization modelling
of observed column densities (e.g. aligned Si II/Si III absorbers) are
validated against our simulations. Our simulations therefore support previous
ionization models indicating that cloud covering factors decline while
densities and pressures show little variation with increasing impact parameter.
