The researchers tested different ways to clean seawater for drinking using a combination of filters and chemicals before passing it through a reverse osmosis system. They found that adding a chemical called FeCl3 to the process helped maintain the filter's performance over time. The best results were seen when FeCl3 was used with sand filtration and ultrafiltration. This combination removed pollutants effectively and produced clean water with low levels of impurities. Sand filtration was good at removing dirt, but not as effective at removing certain types of pollutants. Overall, the hybrid system tested was able to remove up to 28% of organic carbon from the seawater.