# Factors that cause pH to drop



## dp0350 (Mar 31, 2007)

Ok so the pH out of my tap is 7.4 The pH in my tank is 8.4 All the decorations that I have in my tank are some plastic plants and about 15 flat river rocks take from a local stream. My substrate is a natural gravel made for aquariums purchased at walmart. The river rocks are what has to be raising my pH right. It cant be the gravel that is made for aquariums??


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## Mr.Todd (Mar 8, 2007)

Do you have a pH drop or hike? If your pH is dropping (i.e. becoming more acidic) then the rocks from the river may have some sort of trace pyrite or other metal that is oxidizing and creating acid. If the pH is rising then the rocks may contain calcium or other soluble mineral that produces hydroxide ionÃ¢â‚¬Â¦ 

You could always test the rocks by washing them under the tap and then placing them in demonized (distilled) water with a bubbler and monitoring the pH closely. If it changes either way you will know that the rocks are to blame!

Best of luck! 

   b


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## dp0350 (Mar 31, 2007)

*Rise*

Sorry its a pH rise, making the water basic.


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## Lupin (Aug 2, 2006)

dp0350 said:


> It cant be the gravel that is made for aquariums??


There are gravel that even designed for aquarium use will still allow pH to increase.


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## dp0350 (Mar 31, 2007)

*gravel*

Ill pull some gravel out of my tank as well as one of the rocks and vinegar test them.


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## dp0350 (Mar 31, 2007)

*test*

As far as I can tell no fizzing for the gravel and just a small amount for the rocks. Nothing really apparent on either of them though. Ill get rid of all the river rocks asap just in case.


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## fish_4_all (Nov 13, 2006)

Before going too far, test yur tap water AFTER you have let it sit out for 24 hours. Agitating it once in a while will help also. It could be no more than your tap water is actually closer to 8.4 and dissolved gases are making it appear lower. Having a different pH in your tanks than your tap water is normal although I would think that 0.2-0.4 is a normal range of difference. My tap water is almost always 7.2 but my tanks range from 6.8 to 7.6


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