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Ive recently redone my 90 gallon tank. Ive added a couple plecos and catfish. The tank was fully cycled, had a few cichlids in that I just got rid of. So now I have a sultan, vampire, bristlenose, and two jaguar cats, (and guppies). Anyway, I had three pieces of driftwood in before and the tank pH stayed around 7. I recently added 5 more pieces of driftwood and my pH is dropping to about 6.5 or a bit lower. Even if I do a 50% water change it drops overnight. I let the driftwood soak for about a month, I figured all tannins were out. Do I have any options for keeping the pH up besides taking the driftwood out? Also my water is very soft so the pH changes easily. Thanks for your help.

With the fish you list, if the pH is staying at 6.5 or so and not falling drastically lower I don't believe you have to do anything about it.

Mind that you will have to be very diligent with water changes, but if it stays at ~6.5 you should be OK.

If you would like to try to buffer it up a bit, you could add a few small handfuls of crushed coral. Do this slowly, one at a time.
Add a handful. Check your pH the following day. Repeat as needed.

As stated, tjhe pH of 6.5 will be apreciated by the fishes. Still, I can imagine you would not like it to get below say 6. Dropping to 6.5 overnicht does imply the risk of dropping even further - which you will not want

You could measure the KH (carbonate hardness) this is the most importent pH buffering system in a tank - but it does not work below aproximately pH 4.5. At pH 6.5 you should aim at 3 to 5, no more. Normally KH increasing preparations are available at every aquarium (and pond) shop

The wood does, as you assumed, give pH decreasing stuff, but you better not counteract this. Should you add pH increasing stuff, the acids would dissolve more rapidly, resulting in a very fast decay of your wood. This decay will also consume a lot of oxygen.

Bas Pels wrote: Should you add pH increasing stuff, the acids would dissolve more rapidly, resulting in a very fast decay of your wood. This decay will also consume a lot of oxygen.

Just for clarification, if you adding pH increasing chemicals, you will be adding bases not acids to the tank. Getting the KH up to the suggested 3-5 will solve your problem.

HTH

Sorry, I ment the acids in the wood dissolving

I was not very clear

Loads of info on pH and hardness etc here....

http://www.planetcatfish.com/shanesworl ... cle_id=332