Or you can build a skimmer
http://www.thekrib.com/Filters/Busko/

"SteveG" wrote in message
...
I've read somewhere that having Black Mollies will help get rid of this.
So
I tried, it worked. Honest!
http://www.geocities.com/anwestover/...herbivores.htm

"JFM" wrote in message
...


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I have a moderately planted 40 gallon tank. I have a co2 injection
system
and the ph is around 6.8
ammonia: 0 nitrite: 0 and nitrate around 12.5 according to my test kit.
I
have discovered that my tank actually reduces the nitrates in my tap
water
which are at around 25ppm, but that's another story...

Everything is going good, plants are producing an incredible amount of
o2,
described as the champagne effect as I read somewhere.

Anyway problem is I have a strange white oily film on the water surface,
the
origin of which is baffling me. It just appeared a few days ago out of
the
blue, the only difference recently is that the plants are producing a
lot
more o2 than they used to.

Any ideas are most wecome...

JFM