# Texas holey rock and pH



## gfry (Oct 20, 2009)

OK - Here's another noob question. :roll:

I want to put some Texas holey rock in my 55. I don't need to raise the pH or KH. I just like the way it looks. The natural pH of my tap water is 8.2 and KH is around 13. If I add around 40 lbs of holey rock, will it raise my pH higher than it already is?

I *think* I know the answer... Wouldn't it would require more acidic water to cause the rock to leach minerals and raise the pH? (But then again, thinking is what usually gets me into trouble. Sometimes I think I know just enough to be stoopid...) :-?


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## PfunMo (Jul 30, 2009)

I'll join you on that stoopid train.  I would agree with your thinking also. I believe that the effects of any rock (holey or not) are largely blown out of proportion to what actually happens. Seems to me a simple matter. If it can be dissolved into our tanks quickly enough to blow the PH, how come it took nature millions of years to make those holes. Settle for it taking thousands of years and I still feel safe. :wink: Bet you can't take even the pressure from a power washer and get a hole through a holey rock before Christmas.. 
When we first add a rock there may be a jump in PH but that is from the dust we failed to wash off IMO. :?

I notice a lot of folks here in Texas build their houses out of limestone. Guess they don't worry about it washing away? :thumb:


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## Steve St.Laurent (Oct 2, 2008)

My Ph is 8.2 out of the tap as well. I put 140 lbs of holey rock in my 90 gallon and a year later the ph is . . . . 8.2


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## TKC747 (Dec 5, 2008)

I think you need to know the term "buffer" If your pH is 8.2 and you use some stone work to buffer your water then pH will not go up. If your water was 7.0 then pH will go up.

I wish I could explain the term "buffer" better.  I hoope a chemist chimes in for you


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## gfry (Oct 20, 2009)

I do have a layman's understanding of what buffering means. It is the property or properties of water (or any solution, for that matter) that allows it to resist changes in pH. My understanding is that the buffering capacity is directly related to the hardness of the water. Generally, the higher the hardness, the more buffering capacity the water has. I always thought that it was more a function of carbonate hardness (KH) rather than general hardness, but I really don't know if that is true or not. I'm sure there's a LOT more to it than that, though. 

My concern was whether holey rock would leach ions, minerals, or whatever raises alkalinity into the water and cause the pH to go higher than its natural 8.2.

Thanks PfunMo, Steve, and TKC747!


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## wheatbackdigger (May 11, 2008)

PfunMo said:


> I'll join you on that stoopid train.  I would agree with your thinking also. I believe that the effects of any rock (holey or not) are largely blown out of proportion to what actually happens. Seems to me a simple matter. If it can be dissolved into our tanks quickly enough to blow the PH, how come it took nature millions of years to make those holes. Settle for it taking thousands of years and I still feel safe. :wink: Bet you can't take even the pressure from a power washer and get a hole through a holey rock before Christmas..
> When we first add a rock there may be a jump in PH but that is from the dust we failed to wash off IMO. :?
> 
> I notice a lot of folks here in Texas build their houses out of limestone. Guess they don't worry about it washing away? :thumb:


Texas holey rock, my understanding, is a limestone. I've had limestone (not holey rock) in my tanks for two years. It raises the tap PH from 7.6 to 8.2/8.3, no higher. If your tap is 8.2 with buffering capacities, I doubt there will be much effect on your tank water.

Limestone raising PH is not some made up fable or myth. It's a fact and it doesn't take a whole lot of rock to do it. I have maybe 40 or 50 lbs in a 150 gallons of water and I can guarantee the PH is 8.2/8.3 without checking it. I would bet it would take far less stone if it was placed in your filters.

But, like I said, if your pH is already around 8.2, limestone will have little to no effect on the pH. Chemically impossible


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## TKC747 (Dec 5, 2008)

gfry said:


> I do have a layman's understanding of what buffering means. It is the property or properties of water (or any solution, for that matter) that allows it to resist changes in pH. My understanding is that the buffering capacity is directly related to the hardness of the water. Generally, the higher the hardness, the more buffering capacity the water has. I always thought that it was more a function of carbonate hardness (KH) rather than general hardness, but I really don't know if that is true or not. I'm sure there's a LOT more to it than that, though.
> 
> My concern was whether holey rock would leach ions, minerals, or whatever raises alkalinity into the water and cause the pH to go higher than its natural 8.2.
> 
> Thanks PfunMo, Steve, and TKC747!


Ah! thanks now I got it!


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## gfry (Oct 20, 2009)

wheatbackdigger said:


> Texas holey rock, my understanding, is a limestone. I've had limestone (not holey rock) in my tanks for two years. It raises the tap PH from 7.6 to 8.2/8.3, no higher. If your tap is 8.2 with buffering capacities, I doubt there will be much effect on your tank water.
> 
> Limestone raising PH is not some made up fable or myth. It's a fact and it doesn't take a whole lot of rock to do it. I have maybe 40 or 50 lbs in a 150 gallons of water and I can guarantee the PH is 8.2/8.3 without checking it. I would bet it would take far less stone if it was placed in your filters.
> 
> But, like I said, if your pH is already around 8.2, limestone will have little to no effect on the pH. Chemically impossible


That's the answer I was expecting (hoping for) but wasn't sure.

Thanks!


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## AC (Jul 26, 2010)

this is a good example of being able to use the search function to get most answers to questions.

I just bought about 80lbs of Texas holey rock to add to my 125 and was wondering the same thing about possibly having too much and turning the water too basic.


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