Many pet parents have found that Tetra Water Clarifier. helped them clear their cloudy freshwater aquarium water. It’s safe in soft water conditions—the dosage may vary depending on how soft—and can help clump particles together so your filter’s regular operation can remove them. Their line of Tetra pond fish treatments also includes a water clarifier that has helped satisfied pet parents clear their murky outdoor ponds. However, Tetra fish products offer a satisfaction guarantee for their water clarifier, so you can contact them for a refund if the results do not convince you.