# Paver sand



## bigfish93 (Jul 7, 2009)

MinaMinaMina just saved my fishs' lives. I recently added pavers sand to my tank and I love the look of it. However, I completely forgot to do the vinegar test to make sure it is safe for my aquarium. I tested a little bit of it tonight and it fizzed! My pH has been a steady 6.8 the past couple of days that the pavers sand has been in my tank, so my question is, how long is it going to take the paver sand to effect my pH? I really love the look of the sand and don't want to take it out. Is there any chance at all I could leave it in my tank without it effecting my lemon tetra?


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## MinaMinaMina (Aug 28, 2011)

Hey! I actually have a mason jar of some paver sand and water from at least 2 months ago. I could test the pH of that water, and look up the date of when I set it out. But wait, on the other hand, my water from the tap is 8.4 on the API test, and it only measures up to 8.8 I think. So maybe that wouldn't be the best help. But I could test it if you want me to!


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## MinaMinaMina (Aug 28, 2011)

Okay, so I was curious myself, and went ahead and did the test. It looks like I had originally vinegar tested my paver sand on 9.3.11, and here is the thread from that:
http://www.tropicalfishkeeping.com/freshwater-aquarium/how-accurate-vinegar-test-really-79956/

I'm shocked and confused by the results I got tonight, so I will try to be clear so I don't confuse anyone else. 
Ahem...
So, I had established that my paver sand was calcareous with a positive vinegar test. And a sample of my paver sand had been sitting in a closed mason jar of tap water that has a pH of 8.4 for about a month and a half.
Tonight I retested my tap water to confirm the pH of 8.4. I then tested the jar water, and got 8.0. I was confused. So I again tested the jar water, to confirm a pH of 8.0. I do not have a testing kit for hardness.

I don't know exactly how to explain my thoughts, something like- My theory is that my tap water is harder and more basic than the paver sand, and so the pH equalized halfway between the basic paver sand and more basic water. I don't know if that makes sense, and I don't know if that is possible. But something here is def whacky!

I know the paver sand is calcareous, and I therefore know if would raise my pH if my water were acidic. Perhaps someone with a better grasp of geology and chemistry can explain the above stated fall in pH. I don't know! But don't take any of this to mean that I think the paver sand is safe for your tank (or mine). I def don't think that! Ah, I'll think about it more tomorrow, I'm nodding off. Goodnight!


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## bigfish93 (Jul 7, 2009)

MinaMinaMina said:


> Okay, so I was curious myself, and went ahead and did the test. It looks like I had originally vinegar tested my paver sand on 9.3.11, and here is the thread from that:
> http://www.tropicalfishkeeping.com/freshwater-aquarium/how-accurate-vinegar-test-really-79956/
> 
> I'm shocked and confused by the results I got tonight, so I will try to be clear so I don't confuse anyone else.
> ...


When you did the vinegar test, did it bubble and fizz a lot? When I did it, it didn't appear to fizz at first. I could only hear the fizzing if I held the cup up to my ear and listened closely.


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## MinaMinaMina (Aug 28, 2011)

It did fizz a lot, but it took a few minutes for it to kick in. I even vinegar tested some store-bought aquarium gravel as a control. As Byron pointed out in the other thread, vinegar is a pretty weak acid. Bottle #2 of the Nitrate test in the API master kit is a stronger acid than vinegar, and tests done with that or with muriatic acid would be more precise. But he dashed all my hopes of any chance of a false positive. Basically (*rimshot*), if it fizzes at all, its calcareous.

I know its hard to hear, but.... you have such a great pH for S.A. fish (I'm jealous! :-D) and your fish are doing well, so I wouldn't do anything that could possibly mess with it. Just my opintion, of course.

If you wanted to go farther, you could do as I did and sit some paver sand in an inert container with your local water. Take some initial readings of pH and hardness, and re-test every week for a while. See what happens. Good luck!


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## AbbeysDad (Mar 28, 2011)

One always has to be suspect of paver sand as there may be bonding agents in play.
I don't want to confuse things, but the vinegar (and/or other acid) tests may have some slight value, but consider that the reaction of acid on a substance is not the same as the reaction would be with water on a substance. There may be a slight affect on pH over time, but there may only be a relatively slight change.
Just don't use vinegar in your aquarium water! ;-)


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## Mikaila31 (Dec 18, 2008)

All water has a specific buffing capacity, which is based a lot on the hardness. With regular water changes I would not expect the sand to effect your water that much. Your theory is pretty much correct. The vineagar is an acid and has a pH of under 3 usually. Your tap water is very basic for tap water. The pH scale is logarithmic so a pH of 6 is ten times more acidic then a pH of 7. How the sand reacts to the vinagar is gonna be quite different then how it reacts to your basic tap water. Exactly how it will react is hard to say based on the vinegar test. The sand was more basic then the vinegar, but that doesn't mean is more basic then your tap water. Either way with a tap pH of 8.4 its pretty much guaranteed you have some hard water. That hardwater is going to have a good buffing capacity so as a result its going to resist quite a bit to any pH changes. 

Though the vinegar test is a good idea, I wouldn't put a lot of merit on the results unless the test sample erupted with bubbles. It more so tests dissociation. Vinegar with a pH of 3 and baking soda with a pH of 8 react very violently together because they for ions very readily in solution and this allows them to react. Some things don't dissociate well though and how they dissociate in vinegar may not be the same way and/or degree they dissociate in water.


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## MinaMinaMina (Aug 28, 2011)

Okay, I see. So just for kicks- Could I then infer that, because the paver sand dropped my pH by 0.4 points, that the paver sand has a pH of about 7.6? Well, at least when exposed the buffering capacity of my local water? I understand that I could NOT go as far as to say that bigfish93's water of pH 6.8 would rise to 7.2 with paver sand, because of the presumed difference of buffering capacity in our two waters. But could it be presumed that, if I wanted to keep a tank at a pH of 7.6, I could add in my tap water with the pH naturally adjusted to 7.6 and that the paver sand would keep that pH remarkably steady? Now I'm curious. Perhaps the next time I do a water change on my 55g (which is currently at pH of 7.4), I'll put some of that tank water in a jar with paver sand and see what happens to the pH over time.

Science if fun!


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## Mikaila31 (Dec 18, 2008)

Nope because if your gonna change pH its likely buffering capacity is gonna change too since those to are based on SOME similar factors. The paver sands pH isn't actually all that relative here. It is more so interacting with your water at a steady rate. Since your pH is going down that would imply it was less basic then your water, but I'm not quite sure what would make sand act as an acid. Buffering capacity is pretty much set and acts at on optimum at a certain pH. If you add an acid or base there will be little change due to the buffering. Eventually though as you keep adding say an acid you are consuming your buffering capacity. Eventually you will move pH, very slightly at first, but as more buffering ability is consumed the more your pH is gonna be effected. Suddenly the acid that had no effect on the pH does have a pretty large effect since it has consumed all the buffer. What results is a pH crash. This can actually happen in tanks with a very small to zero buffering capacity just as a result of the nitrogen cycle. 

Buffering capacity is one of the reasons you can't escape from doing water changes. Even if wastes never build up in a tank your buffering capacity does get very slowly consumed as it resists changes. If that buffering capacity is not replenished via a water change it will eventually become lost and then you will lose all stability. If you have a good buffering capacity it can take a long time for it to get used up, but eventually it will happen.


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## Mangrove Mike (Oct 15, 2011)

bigfish93 said:


> MinaMinaMina just saved my fishs' lives. I recently added pavers sand to my tank and I love the look of it. However, I completely forgot to do the vinegar test to make sure it is safe for my aquarium. I tested a little bit of it tonight and it fizzed! My pH has been a steady 6.8 the past couple of days that the pavers sand has been in my tank, so my question is, how long is it going to take the paver sand to effect my pH? I really love the look of the sand and don't want to take it out. Is there any chance at all I could leave it in my tank without it effecting my lemon tetra?



I think the change to your PH will be instant. Monitor carefully and only add chemicals to raise or lower your PH slowly so as to not affect your fish.


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## bigfish93 (Jul 7, 2009)

Mangrove Mike said:


> I think the change to your PH will be instant. Monitor carefully and only add chemicals to raise or lower your PH slowly so as to not affect your fish.


Thanks Mike. The paver sand will be coming out tomorrow as I don't want to take any chances. My pH has already gone up by .1, so I will be removing the pavers sand and replacing it with some oak leaves.


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## AbbeysDad (Mar 28, 2011)

bigfish93 said:


> Thanks Mike. The paver sand will be coming out tomorrow as I don't want to take any chances. My pH has already gone up by .1, so I will be removing the pavers sand and replacing it with some oak leaves.


.1? So basically, it didn't change. So why are you worried? <rhetorical>


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## Mikaila31 (Dec 18, 2008)

Just a note that you should not use any chemical additives with the intent to change pH.


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## bigfish93 (Jul 7, 2009)

AbbeysDad said:


> .1? So basically, it didn't change. So why are you worried? <rhetorical>


The longer I leave it in the tank, the more my pH is going to increase. It's only been in there for a couple days, so after a month it is going to make a significant change. Byron already told me that sometimes it takes a couple days or sometimes weeks before it really starts to drastically change the pH and I am not going to wait and find out.


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## AbbeysDad (Mar 28, 2011)

bigfish93 said:


> The longer I leave it in the tank, the more my pH is going to increase. It's only been in there for a couple days, so after a month it is going to make a significant change. Byron already told me that sometimes it takes a couple days or sometimes weeks before it really starts to drastically change the pH and I am not going to wait and find out.


As has been discussed here many times, not all (paver) sand is the same - but when in doubt, take it out


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