# [Wet Thumb Forum]-Driftwood Dropping BOTH kh and gh



## imported_BSS (Apr 14, 2004)

About two weeks ago, I posted about kh/gh drops in my 46g. Per other posts in the forums, driftwood is a frequent culprit of kh declines, but not gh. This was confirmed by Roger. My driftwood consists of five pear-grapefruit sized pieces of dark, self-sinking "Asian" driftwood.

Well, here's some results I've gathered. On 10/1, I removed two pieces of driftwood and put them in a plastic container and set them outside (#1). On 10/4, I removed another pieces and put it in a slightly smaller container (#2), plus I set out a plastic cup of straight tap water (#3). Here's the measurements (shown as drops of kh / gh):

.................#1........#2........#3 (I wish they'd line up!!)
10/1 2200....7/10......n/a.......n/a
10/3 1500....7/8.......n/a.......n/a
10/4 2100....6/7-8...6-7/10-11.6-7/11
10/5 2130....6/7-8...6-7/9-10....7/10
10/6 2130.5-6/7.....6-7/9.......7/11
10/9 2100....5/7.....5-6/8.......7/11

Can anyone explain the dropping gh? How would the driftwood do this?

Per ninob, I might be able to address the kh issue through boiling the driftwood. Would this address the gh aspect also? Or do I just have toxic driftwood







?


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## imported_BSS (Apr 14, 2004)

About two weeks ago, I posted about kh/gh drops in my 46g. Per other posts in the forums, driftwood is a frequent culprit of kh declines, but not gh. This was confirmed by Roger. My driftwood consists of five pear-grapefruit sized pieces of dark, self-sinking "Asian" driftwood.

Well, here's some results I've gathered. On 10/1, I removed two pieces of driftwood and put them in a plastic container and set them outside (#1). On 10/4, I removed another pieces and put it in a slightly smaller container (#2), plus I set out a plastic cup of straight tap water (#3). Here's the measurements (shown as drops of kh / gh):

.................#1........#2........#3 (I wish they'd line up!!)
10/1 2200....7/10......n/a.......n/a
10/3 1500....7/8.......n/a.......n/a
10/4 2100....6/7-8...6-7/10-11.6-7/11
10/5 2130....6/7-8...6-7/9-10....7/10
10/6 2130.5-6/7.....6-7/9.......7/11
10/9 2100....5/7.....5-6/8.......7/11

Can anyone explain the dropping gh? How would the driftwood do this?

Per ninob, I might be able to address the kh issue through boiling the driftwood. Would this address the gh aspect also? Or do I just have toxic driftwood







?


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## Roger Miller (Jun 19, 2004)

That's a very interesting test. I can only speculate about how the wood would lower both KH and GH.

If the driftwood is decomposed enough then it might behave a little like peat. Acids are formed in the wood by bacterial or fungal activity. The acids are not readily soluble, so they stay in the solid material, but they release hydrogen ions into the water. That leaves the wood itself with a net negative charge. The hydrogen ions released by the wood attach to bicarbonate in the water and lower the KH. Positively charged calcium and magnesium ions are attracted to the negatively charged wood and so are taken out of solution, which lowers the GH.

That differs from what some people seem to get from wood, which is a drop in KH without a drop in pH. In that usual case the acids produced in the wood are soluble. Since the acids enter the water the wood never gains an electrical charge and the peat-like softening effect isn't important.


Roger Miller


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## imported_BSS (Apr 14, 2004)

Thanks for the feedback, Roger. I'll boil one of the pieces and see if it changes anything. Any guesses what should happen?


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## Roger Miller (Jun 19, 2004)

If it's acting like peat then boiling won't do much at all. 


Roger Miller


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