Nitrates are 0ppm and temp of the tank is 74 degrees Fahrenheit. I've
tried the water change in intervals of 20% at a time every 3 days for 2
weeks and had little success. Is there a chance that it's some sort of
algae? Besides buying a diatom filter for it, is there anything else I
could try? Right now I'm using carbon in the media baskets in both of
the penguin 330s.

Thanks
Wendy

Geezer From The Freezer wrote:
You didn't state what your nitrate parameters are
(i'm sure it's not that). Have you considered doing
a 30% change every two days for a week and see if that
gets rid of the "haze" for at least a while?

Also what temperature is your tank at?