Is it at all green? Get a white paper or styrofoam cup and fill it with tank water to check the color.
And how long have the tank and filter been running?
You can always get purigen for water polishing, but water polishing is for really fine-tuning clarity. It sounds like either basic filtration issues (which may clear up over a period of a few days) or green water (which could be fixed by a blackout period, a UV sterilizer, water changes, lower lighting, more CO2 and fertilizers, or any combination of the above).