Yellowing of the water when using cork

["Gary Whitt" <gwhitt at koedcandies_com>]

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Date: Fri, 18 Oct 2002 11:54:44 -0700 (PDT)
From: Neal De Pape <neal_depape at yahoo_com>
Subject: Input or Output from a Canister to a CO2 reactor?
<snip>
Also, I've purchased some cork for backgrounds in my tank and I'd like to
avoid the yellowing of the water I've seen when using cork previously. Does
anyone have any ideas what I could do over and above just soaking the cork
for a long time? Would a bleach/water soak help? What would I have to do to
make sure all the bleach was out of the cork?
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I've done two tanks, one this spring and one late this summer. The first is
a 65g with cork bark covering the back wall. The second is a 54g corner bow
with cork bark on the corner walls and cork retaining walls breaking the
bottom into three beds. There is way more cork in the second tank and way,
way more sqft of cork per gallon than the first tank. I milled flats along
the back edges to give a good continuous glue seal to the glass. The first
tank completely stopped yellowing the water in about 6 weeks and the second
tank is still yellowing the water slightly after 8 weeks. Considering it's
essentially a forever thing, a few weeks of flushing out the tannins during
tank start up isn't a serious hard ship. You'll want a good, clean, dry cork
to glue to the glass. For convenience and time's sake, that'd put flushing
out the tannins after the tank is set up. Cork bark is a very dramatic
natural looking background and a perfect place to tack those rhizome plants.
Once the plants settle in and orient naturally, it looks super while
providing housing and hiding for some of the tank's shy denizens. Credits
and thanks to APD, several APDers discussing cork and cork bark last winter
and finally, my wife for giving up the dining room. When I convince her to
give up more room, the next tank will have cork bark, too.
8~)>

Gary Whitt
Buffalo - the city of no illusions