Rocks

[hermitpermit]

can u use rocks u find outside for your aquarium if so what precautions do you have to take

 

[rvm]

put some vinegar on them, if it bubbles, then it can't go in the tank. If not then boil them and scrub them well, and you should be OK.

 

[FrankSlapperinni]

If the vinegar bubbles, this means the rock is made of limestone. If your tank is overly acidic, or if your keeping fish like African cichlids, limestone is a very good element to have in your tank, as it raises and stabilizes pH. But if you have a typical community of neutral to acidic water loving fish, them you should not be adding it to the tank.

 

[gixer]

put some vinegar on them, if it bubbles, then it can't go in the tank. If not then boil them and scrub them well, and you should be OK.

untrue....like said here and here

 

[digital_run]

I've usedrocks from my backyard...i just boil them in a corn pot. I wouldn't use and rocks that have a metalic look to them...make sure they ar rounded and not sharp so your fish dont cut themselves and you should be fine. HIH

 

[rvm]

untrue....like said here and here

Where does it say that is untrue. I wrote that if it fizzes it's bad. that is exactly what that thread says!!!!!

 

[gixer]

untrue....like said here and here

Where does it say that is untrue. I wrote that if it fizzes it's bad. that is exactly what that thread says!!!!!

yeah but it was pointed out in that thread that vinegar doesnt work on a lot of rocks..

i have tested with vinegar on rocks i know will raise kh and it does not fizz...

the vinegar test needs to be ditched IMO its not strong enough acid

 

[gixer]

taken from the skeptical aquarist..

basically all rocks are "aquarium safe" with a few exceptions: calcium and magnesium-bearing rocks, for example. Limestone (which is basically calcium carbonate) and dolomite (which adds some magnesium carbonate) often have a soft and chalky look. They are easily scratched with a knife (less than 4 on the Mohrs hardness scale). Sometimes your thumbnail will even leave a mark. Often these sedimentary rocks reveal their striated bedding planes. But sandstone can have some "lime" content too. Imbedded fossil shells and shell fragments are a giveaway, if you find them. Remember that the minute shelly debris that forms limestones may have been mixed with various amounts of muddy silt, bearing organic materials that make the limestone dark, or with yellow and brown iron oxides, so the resulting lime-bearing rocks may not always be as blinding as the White Cliffs of Dover. The calcium and magnesium content of these rocks will slowly dissolve in water, the dissolving carbonates increasing the buffering and raising the pH. So calcium- and magnesium-bearing rocks are undesirable--— except in your Rift Lake aquarium, where you want that alkalinity. The "honeycomb limestone" you can find in central Texas gives a vivid impression of the way acidic groundwater can dissolve away carbonate rocks. Marc Elieson illustrates these bone-white limestones like calcified sponges in his Rift Lake aquaria, where they contribute to the carbonate buffering.

How to test for carbonates. Everyone you ask will recommend the old trick of putting a teaspoon of vinegar on a suspect rock; if it fizzes it's going to raise the pH. That would be clear enough, but what if it doesn't produce a bubble?

Some prep is necessary. PaulK posted at AquaLink, 13 Aug 2003:

"The acid test would depend on the strength of the acid, but would also depend on the surface you are testing as well. In order to be accurate, a fresh surface should be tested. It is possible that the rock may have a carbonate residue, which would effervesce if acid is applied, though the actual rock itself may be something that contains no carbonates.

On the other hand, a rock may be a carbonate and yet may not effervesce readily when acid is applied. Dolomite, for example, must be powdered to react with an acid."


Household vinegar has never worked for me. A friend suggests that pickling vinegar is more acidic than the common salad dressing kind I was using. I might even recommend instead that you put a suspect rock in a bucket with enough water just to cover the rock. Test the pH now and test again after a week or so. If the pH hasn't noticably risen, figure that the rock is "aquarium safe." Does this sound too lackadaisical?
Some aquarists test using muriatic acid, which is a 20% solution of hydrochloric acid, available at your hardware. For heaven's sake be careful with this intensely caustic stuff.

 

[rvm]

untrue....like said here and here

Where does it say that is untrue. I wrote that if it fizzes it's bad. that is exactly what that thread says!!!!!

yeah but it was pointed out in that thread that vinegar doesnt work on a lot of rocks..

i have tested with vinegar on rocks i know will raise kh and it does not fizz...

the vinegar test needs to be ditched IMO its not strong enough acid

Ahhh, I get it now. Still, it's better than just chucking anything in the tank though!!!

 

[clutterydrawer]

If you want to "fizz test" a rock you'd be better using hydrochloric acid or if you really ahve to, distilled white vinegar.


To be on the safe side, just leave the rock in a bowl of water, test the pH before and after, and see if it's changed.