# UV filter: Green cloudy water >>>> White cloudy water



## rich815 (Jun 27, 2007)

Two weeks ago I scooped out about 6-8 cups of my substrate from the front center of my 72 gal wanting to create a more sloping foreground. It worked, and looks great. Unfortunately, although I did a big water change after that it was apparently not enough, and I must have caused an ammonia spike because within a day or two I was hit with a big dose of green water. I hooked up a small 9w UV filter I've had for a couple years but suspected the bulb might be a bit worn out. After 3-4 days of nothing but more green and more cloudiness I figured the ol' 9w UV bulb has had it. I went into a local Petsmart on the way home from work last night and they had the big 24w UV filters, similar to my 9w one (long, flat elongated bulb housing, small rectangle blue foam inlet, and small power filter attachment) but it was MUCH longer and bigger than the 9w one. It was about $58 so I bought it. Hooked it up last night. This morning the green is pretty much gone from the water to be replaced by white, milky cloudiness. Is this normal? Should I run the UV filter a few more days? Will the white, milkiness go away with normal filtering (I have eheim 2026 and 2028 running). Anything I need to do now to get rid of the white cloudiness short of a diatom filter? Thanks.


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## rich815 (Jun 27, 2007)

Never mind. Two good 50% water changes, UV filter still running. I am crystal clear again.


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## JugBandBanjoCat (Apr 26, 2006)

I just went through this also. I was in a hurry to go out of town on the day I was due for a water change. As I was doing the change I decided that I had better trim some of the plants of they'd be growing out of the tank by the time I got back. A quick trim lead to rearranging half the tank. I came back home to green water. I fired up the UV filter for the first time since I had bought it. It ran for 2 days and I could tell that the water was less green, but not clearing up any more so I did a water change. Ran two more days and the water was a foggy white color. Did another water change. Now the water is very clear. Do you supposed the white cloud is the dead algae? Using the UV filter was a lot easier that getting rid of the green water without it. I've been thinking about picking up a HOT magnum to use along with the UV for the next time it happens and to use as a weekly water polish.


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## Diana K (Dec 20, 2007)

White cloud is the dead algae, and it is adding to the bioload as it decays. 
Much better is to do as big a water change as you can before starting the UV, to remove a lot of the algae. Then keep up the water changes as the UV kills the algae. 
Running a diatom filter in conjunction is fine, but you will need to clean it frequently. 
a) it will plug up
b) stuff in the filter (dead algae, in this case) is still decomposing in the system.


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## JugBandBanjoCat (Apr 26, 2006)

Diana K said:


> White cloud is the dead algae, and it is adding to the bioload as it decays.
> Much better is to do as big a water change as you can before starting the UV, to remove a lot of the algae. Then keep up the water changes as the UV kills the algae.
> Running a diatom filter in conjunction is fine, but you will need to clean it frequently.
> a) it will plug up
> b) stuff in the filter (dead algae, in this case) is still decomposing in the system.


Thanks for confirming that the white cloud is the dead algae. Good tip also to do a water change before starting the UV. As this was my first time using the UV for green water I wasn't sure if I should do a water change, that usually not the thing to do with that algae. Makes sense to do it with the UV though. I think I'm just trying to come up with an excuse to pick up a HOT Magnum. :-D


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