Abstract : Domestic waste water, whose presence can reach 60-70 percent, is currently the most prevalent pollutant in water bodies. Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) are components of domestic wastewater. Biological treatment is one method of wastewater management. Some researchers employ algal biofilters to reduce nitrogen and phosphorus using biofilter technology. Objective To compare Coral and Coconut Shell Coir Biofilter Media for Reducing BOD, COD, and TSS Levels in Domestic Wastewater (Grey Water). This sort of study employs a quasi-experimental, pretest-posttest approach. The pretreatment test was achieved by assessing the parameters of the wastewater prior to treatment, whereas the posttreatment test was conducted after treatment. With this design, observations or measurements are performed multiple times (both before and after treatment) to reduce the influence of external circumstances. According to the study's findings, the BOD parameter test results utilizing coconut shell coir media had a significant p value of 0.055. Using the paired t-test, it was determined that there was a substantial drop in BOD levels before and after processing, with a p-value of > 0.05, thus H0 was rejected and Ha was allowed. In addition to the rock media test results, the TSS parameter has a significant p value of 0.003. Using the paired t-test, it was shown that there was a significant drop in TSS levels before and after processing with a p value 0.05, so H0 was rejected and Ha was allowed.