Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
If there is any way to set up a constant water change, do it.
The more water that flows through the more the tannins are diluted, so the clearer the water will look.
If you cannot do that, then do as many water changes, as large as possible. Again, you are removing the maximum amount of tannins that way.
Both Purigen and activated carbon will remove tannins, but in a bad case like this you cannot just add them and forget them. They will fill up fast. Here is how I would do this:
Get 2 bags of Purigen. Always have one in the filter, and one being rejuvenated. Swap them every few days. If you can rejuvenate them before they are fully saturated it seems to make them last longer.
Swap out the activated carbon weekly or more often (every time you swap out the Purigen). It gets filled and cannot be rejuvenated by any method available in the house.
Here is how to tell when to change these media: If the water is starting to get lighter, then these media are still working. If that 'getting lighter' no longer happens, then these media need rejuvenating (Purigen) or replacing (AC).
The substrate will keep on releasing tannins. There is no way to make it do this any faster in any significant way. Removing the tannins may make it go faster, and warmer temperatures can probably help, but any help from these methods is marginal at best. The substrate simply has it own timetable, and that is that.
What to do with the remaining substrate:
Start the mineralizing as soon as you can, then set up another tank. Let us know how long the tannins lasted in this treatment. I think if you do enough water changes while it is mineralizing that will help a lot, but you will still see some coloring in the water.