Bogwood Still Releasing Tannin

[Guest Brock]

So I'm in the process of setting up a new tank, and I have some bogwood. I soaked it in a bucket of water for a week before I introduced it to the tank.

Now, almost a week after filling the new tank with water, it's starting to discolour the water, with what I believe is tannin (is this correct?).

There are no fish in the tank, just yet. But I just wondered if anyone knew if this was harmful to fish, and if the filter would eventually purify the water.

What would you do?

[denniss]

Brock - Not familiar with bogwood, but I wouldn't be happy with the fact that it is still leaching tannins. I would guess that it is likely to do this for some time. Even if not harmful, who wants stained water? I'd let it leach in the bucket until the water stays clear.

Assuming that the color is caused by tannins, they shouldn't be toxic. I would guess that the color is removable by activated carbon.

Check your pH? If on the acidic side, the water could be contributing to the issue.

Dennis

[Fishmerised]

It sounds like your bogwood isn't old enough or wasn't actually submerged in water as it aged.

If the colour of the water is a yellowish brown then I suspect it is tanin and depending on the size of the log and your tank it will lower the pH.

Good idea about using charcoal to clear the water.

You could try boiling the bogwood for an hour and see if that helps.

[rwersted]

I would usually take me one month to get a new piece of wood soaked and ready for a tank. Then I still would have a couple of weeks of colored water. I agree with the boiling, I usually replaced the soking water with hot water, and I would chnage the water 2 times a day. Regular water changes will reduce your water coloring but to my knowledge the tannins are not harmful in small doses because some people like the effect that it brings to the water, but I am not 100%. I have just never had a problem.

[daryl]

There are bogwood type pieces of wood that are sold in pet stores - but here is where you need to be a bit careful. Any wood piece that is sold for the purpose of reptile tanks most likely has been treated with chemicals with "anti-biotic" activity. Wood treated in this fashion is NOT meant to be submerged in water as in a fish tank. It would be very harmful to the fish.

If the wood you have is simply something you found or made, etc. it should be fine to use after seasoning. Have you ever kyacked in the swamps in the south? The water there is dark brown - coffee colored from all the tannins released from the fallen wood. The fish that live in the tannin filled water thrive.

Tannin can be growth inhibitor in some fish and, being an acid (weak), it can change your pH, possibly. But in general, it is not specifically toxic to the fish. I would, however, suggest that you age your wood for a longer time - to remove as much as you can. Be aware that real wood also will break down (as does anything organic - faster when submerged) and keep an eye on the wood piece over the year. Wood decomposing in the water will also change pH.

Boiling the wood at least one time for at least 10 minutes at a rolling boil is a good idea to disinfect any piece of wood that you have found "in the wild".

I do not think that carbon will bind tannins from the water - or at least not easily. It would require a very LARGE amount of carbon to take care of the concentrations that make up visible orange/brown tannin in the water.

[Guest Brock]

Thanks Daryl. I'm going to wait a few more days before I introduce any fish. Do a water change or two beforehand, too.