Quote:
Originally Posted by JKUK  Is the tannin level likely to stabilize or even decrease over the very long term? |
Tannins could decrease, depending on the tank environment:
- strong lighting would photo-oxidize the tannins
- aeration would encourage faster bacterial decomposition (most tannins resist bacterial decomposition, which is why they accumulate)
- decomposition of soil organic matter and the resulting tannin production slow enough that tannins get destroyed faster than they accumulate (this is why well-established NPTs don't accumulate tannins)
For your tanks (no water changes for 6 months and tannins accumulating), I recommend water changes and/or adding charcoal to the filters. At some point, the tannins may absorb so much light that they inhibit plant growth.