Heterochromatin marked by H3K9 methylation and DNA methylation is vital for epigenetic regulation. Recently, we reported the recruiting factors ZNF512 and ZNF512B for SUV39H proteins that are essential for heterochromatin initiation. Here we report mechanisms that suppress suboptimal heterochromatin formation, in which a hit from an unbiased screen regulates global heterochromatin distribution. In addition, DNA methylation loss at heterochromatin regions is a hall mark of aging associated DNA methylation clock, and we report an intervention strategy that greatly slows the decay of heterochromatin methylation profile.