  We study the 3d $\mathcal{N}=4$ RG-flows triggered by Fayet-Iliopoulos
deformations in unitary quiver theories. These deformations can be implemented
by a new quiver algorithm which contains at its heart a problem at the
intersection of linear algebra and graph theory. When interpreted as magnetic
quivers for SQFTs in various dimensions, our results provide a systematic way
to explore RG-flows triggered by mass deformations and generalizations thereof.
This is illustrated by case studies of SQCD theories and low rank 4d
$\mathcal{N}=2$ SCFTs. A delightful by-product of our work is the discovery of
an interesting new 3d mirror pair.
