Elephant skin rock

[FishyLady]

I spotted a piece of this in the fish store, I had never come across it before and it s very decorative; I asked an assistant is they were inert and he assured me they were. When I went to the counter to pay for it I thought I would just check again so I asked the girl is this stone inert? she looked at me puzzled she is foreign and I assumed she didn't understand my question so I asked her if the stone would affect the chemistry of my tank water and she no not at all so I purchased it.
Yesterday evening I looked it up on the computer, and it said " Slightly raises water hardness " not sure of the definition of " slightly'" but I'm
not happy. I wanted to put it in the tank which houses corydorus and ember tetra they have a large piece of driftwood in the corner which is really old now but it still turns the water brown and I was hoping to replace it with this rock. Your thoughts or opinions on doing this would be really helpful

Val

[Bas Pels]

Frankly, I don´t believe in `slightly`.


ths stone does contain calciumcarbonate, and thus will raise the hardness. How much? That depends on the chemistry of your tank. Acidic water will dissolve more than neutral of basic water. Your water being soft helps a bit, but pH is much more important.

Then, let´s assume the situation is such that 0.1 gram a day of calciumcarbonate will dissolve. Obviously, in a large tank this will not matter so much as in a little one, and frequent waterchanges will further nullify this influence.

Let´s further assume the rock is 2 kilos and contains 10 % calciumcarbonate. That is, 200 g of the stuff, taking 2000 days to dissolve in this situation. However, after a while less and less will dissolve. 4000 days will be a better estimation. That is 11 years. This is to show that outwaiting this dissolving period will not really work - it´s too long

You could increase the dissolving speed, by putting the rock in acid. but in such a case, assuming dayly acidchances, it will still take months.

Lastly, I think your fishes are not that sensitive towards slightly harder water

[FishyLady]

Thank you for your answer, I just know that if anything happened to one of them I would immediately blame myself and that rock.
thanks again,

Val

[FishyLady]

I poured a small amount of vinegar on the rock and it didn't " Fizz " or react at all, so doesn't that show that there isn't much calcium carbonate in it?? or isn't this a reliable test?

Val

[Diana]

Vinegar can help.
1) Scratch the rock to expose fresh rock.
2) Pour on some vinegar.

Other tests:
Put the rock in some water that is similar to how you will be running the tank. Test GH, KH, pH and TDS. every few days for a couple of weeks. (say... 4 times over a 2 week period)
If these values stay stable or rise only very slowly, then the rock is OK.
If these values rise significantly then the rock is not good in that particular water chemistry.

[Bas Pels]

While I think Diana proposes a good test, I woould perform it slightly different: I would use a lower pH.

The lower the pH, the more will dissolve. That is, you get a faster measure. No change in a month, " pH 1 point lower will imply no change in a year in your tank

With tregard to vinegar, the vinegar sold for human consumption is not concentrated enough. In NL we also have vinegar sold for cleaning purposes, this is more concentrated, and usable in the bubble test. You might have it in your country. Alternatively, you could go to an Asian shop, looking for vinegar spirit. This is also more concentrated.