Planted Tank Guru
Join Date: Jul 2010
Location: British Columbia, Canada
Keep doing frequent water changes- that will continue to dilute the tannins.
Don't know what kind of filter you have in your tank, but if you can fit a small bag of Seachem Purigen anywhere in the filter compartment, that will make a huge difference in clearing up the water, and quickly.
If you can't fit it in anywhere in that filter, add an Aqua Clear 20 HOB filter to your tank and place the Purigen in it, along with some filter floss as well. If you have no livestock yet - simply replace your existing filter with the AC 20. If you have livestock, allow the HOB to become seeded with beneficial bacteria for a couple of weeks, then remove the original filter.
The AC HOB will do a good filtration job in your 6.5 gal.