Dick wrote:
On Wed, 22 Jun 2005 08:57:46 -0400, Steve wrote:


Steve, I will no longer refer to my water as "crystal clear!" While
doing my partial water changes in the 3 ten gallon tanks today, I
could see a brown tint in the tank water in comparison to the tap
water.

Now, are you and Troy suggesting any harm coming from the D.O.C. or
seeking maximum clarity?

If you are suggesting harm, in what form would it be noticed to the
fish or plants?

Unless there is harm indicated, personally, I would not want to commit
my self to regular charcoal changes every 2 or 3 weeks to rid this
brown hue which I didn't even notice without you and Troy mentioning
it.

dick

Spotte, Stephen. H. 1970 Fish & Invertebrate Cultu Water Management
in Closed Systems. Wiley-Interscience. New York. I think this is the
library book I read in early 90's that talked about D.O.C. Spotte was
curator of a large public aquarium at the time, and a big proponent of
biological filtration and also activated carbon. He described carbon
reactors made from empty oil drums!! Spotte presented some evidence that
D.O.C. can inhibit the growth and health of organisms.

For home aquariums I agree with you and think that water changes and
filter cleaning should keep D.O.C. and other nasties below harmful
levels. Carbon can produce crystal-clear water however, and that's why I
sometimes like to use it. It also lets me be a little lazier about
maintenance (?).
Steve