# How much do rocks change ph?



## DrMiller357 (Apr 1, 2011)

I know that rocks change ph but does it stop at some point or just keep rising? My water is already pretty high at 7.6-8(ive got playsand in the tank) it comes out of the sink at 7.4-7.6 will rocks that raise ph really effect my water, or will it be about the same?

I know of a place where i can get some rocks but some are layered and other i just cant realy tell what they are. Ive done the vinigar test on them and they passed but some are kind of brittle so im thinkin it will change the ph. Would it be safe to put these in my tank after cleaning them and not have to worry about it effecting anything?


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## Fishy Freak (Jun 1, 2011)

If they passed the vinegar test they should not alter the Ph at all. Are you buying them? If so ask what type they are, If they are found rocks why not test them by putting in a bucket for a month and testing the water.


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## DrMiller357 (Apr 1, 2011)

here is a pic of the rocks i found


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## lohachata (Jan 27, 2006)

the layered one kind of looks like a sandstone...they should be ok for your tank....the only rock that i have ever had change my PH was tufa and texas holey rock..


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## emc7 (Jul 23, 2005)

Sandstone is a sedimentary rock that can have quite varied composition. Some sandstones will up your pH like limestone or calcite. If you fish are fine at 8, they will likely be fine at 8.2, don't sweat it. I find 'river rock' that looks like granite doesn't seem to affect pH. Soak for a week in a bucket of water and test pH.


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## blindkiller85 (Jan 8, 2011)

2 rocks that I know for sure will never affect PH are granite and quartz. Neither are a porous rock that absorb anything nor release anything other than what's on the surface. As I understand it atleast. There's a 16x12 piece of granite in my tank holding my driftwood down, and a 5x5x4 piece of quarts. pH holding steady as always at 7.8.

Sandstone may or may not. Depends on it's composition entirely. Vinegar test passed, then no worries, hopefully. 

Honestly though I would venture out more to find different rocks unless you're completely satisfied with the ones you have there. Just my .02



emc7 said:


> Soak for a week in a bucket of water and test pH.


^that. Test before putting it in and then a week later. Will give you a very very accurate judgement.

As far as answering your question, if it does affect your pH after the vinegar test, it will be slow and not much flux. Limestone or calcite as mentioned above, will raise it relatively slow, but steadily to above 8.0 typically.


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## lohachata (Jan 27, 2006)

when i was keeping and breeding african cichlids (mostly mbuna) my tanks were set up as such...
40 gallon long....UG filters....dolomite substrate...enough tufa rock to almost fill the tank.
the PH was always steady at 8.4....
a heavy carpet of algae was allowed to grow on the rocks and sides and back of tank as many africans feed on algae.30-40%water changes every week..temps at 80 F....
not a lot of other rocks will affect PH ; but it is always good to test them before adding them..the bucket test method is about the best way...fill the bucket and test PH...put the rock in and test 1 week later....that will give you an idea of how much it will affect your tank..keep in mind that the effects will be slower in the tank due to water volume.


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## DrMiller357 (Apr 1, 2011)

Here are some more rocks i found, any advise on id or tank safe would be helpfull, just rinsed them so they may be alittle darker. Btw bringin 40 pounds of rocks uphill for 2 miles is good exercise.. Really good exercise


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## Fishy Freak (Jun 1, 2011)

Do you think a week would be long enough to test? I thought a month would be best to be sure.


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## emc7 (Jul 23, 2005)

A week would be enough for me. A month is more thorough, but if you see no change in a week, the odds of a drastic pH effect is pretty low.


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