Re: Green water

>From: gomberg at wcf_com (Dave Gomberg)
>Date: Thu, 07 Sep 95 07:00:00 PDT
>Subject: Green water
>Now my water is crystal clear (finally).  It cleared by itself (using a small
>hang-on-tank filter with polyester batting in it) over a period of several
>weeks.  But now the water has a residual green tint to it (sort of like there
>was some food coloring in it).  I am running the same filter with carbon in it,
>but the green doesn't seem to be disappearing fast.   Any ideas?

Water with a green tint probably means that it has suspended, single cell
algae, also know as green water. This is very common with new setups. For
some, but not all types of suspended algae, they can be filtered out with a
diatom filter. If the green water is thick, then you may have to change the
diatom powder more than once and run the filter again before the water will
completely clear - to become truely crytal clear. Unfortunately, some algae
are less than one one micron in diameter and cannot be filtered with a
diatom. In this case you have to resort to more drastic measures - either
starve the algae, by limiting its food, like limit feeding and not add any
balanced fertilizers; or, supply more nitrogen to cause the plants to grow
faster and thereby, eliminate some of the trace elements. The plants have a
reserve to keep them going. In both cases, fast growing plants are needed. I
have not found that temporarily reducing the light is a good solution, but
it can't hurt. If you don't have any fish (or want to remove the fish) then
you can add daphnia which will feed on the algae.

         Neil Frank, editor of The Aquatic Gardener
Visit the AGA home page at <http://blake.oit.unc.edu/~fish/aga/>