  Model-independent parametrisations of modified gravity have attracted a lot
of attention over the past few years and numerous combinations of experiments
and observables have been suggested to constrain the parameters used in these
models. Galaxy clusters have been mentioned, but not looked at as extensively
in the literature as some other probes. Here we look at adding galaxy clusters
into the mix of observables and examine how they could improve the constraints
on the modified gravity parameters. In particular, we forecast the constraints
from combining Planck satellite Cosmic Microwave Background (CMB) measurements
and Sunyaev-Zeldovich (SZ) cluster catalogue with a DES-like weak lensing
survey. We find that cluster counts significantly improve the constraints over
those derived using CMB and WL. We then look at surveys further into the
future, to see how much better it may be feasible to make the constraints.

Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology