Rock

[Rhino]

So I will soon be starting my 55 project tank. For a background I want something like stacked stone pieces held by silicone and then make a cave and overhang on one side. My question is: which type of rock or stone should I use. Naturally I want something aquarium safe that will not alter water chemistry. Any ideas in what to use and where to get it from would be most appreciated.

 

[jcolon]

So I will soon be starting my 55 project tank. For a background I want something like stacked stone pieces held by silicone and then make a cave and overhang on one side. My question is: which type of rock or stone should I use. Naturally I want something aquarium safe that will not alter water chemistry. Any ideas in what to use and where to get it from would be most appreciated.

Either go with Slate, which naturally is a flat shaped rock, or Granite. Both come in various colors, are easily found in home improvement stores / gardens, or stores that do stone countertops etc. Both rocks are chemically and physically tough rocks that do not alter water chemistry. You can also get flat granite tiles if you want that flat rock look.

 

[zparticle]

If you buy anything at a home improvement store make sure to ask if they chemically treat the rocks. I nearly killed all my fish making that mistake.

 

[Lowryder]

I like slate or shale. A good test to makke sure it won't change your water chemistry is to get yourself a small bottle of 'ph up' (this is the only thing you should ever use a ph product) and put a few drops on the rocck. If it reacts and bubbles then the rock is not aquarium safe. Hydrochloric acid will do the same.

 

[jsoong]

Get the rocks from a pond supply place ... the rocks should be fish safe. <But ask to be sure.> Slate is prob the easiest to use. If you can't find natural slate, you can get slate tiles from HD, etc. & break it up with a hammer. Just make sure it is not sealed or treated in any way. <If you are really lucky, some HW stores will let you have broken slate tiles for free or cheap.>

 

[Rhino]

I like slate or shale. A good test to makke sure it won't change your water chemistry is to get yourself a small bottle of 'ph up' (this is the only thing you should ever use a ph product) and put a few drops on the rocck. If it reacts and bubbles then the rock is not aquarium safe. Hydrochloric acid will do the same.

Won't vinegar do the same?

 

[Lowryder]

Won't vinegar do the same?

I can't give you an answer on that one. In theory it should, as its ph is 3.

 

[Rhino]

I have always heard the vinegar test but not the others.

 

[jsoong]

Vinegar is a weak acid (esp. the ones in the grocery store that is diluted to 5% or less), so you might not notice a reaction as it will be quite slow. Using stronger acids - pH down, muriatic acid (HCl from hardware store - for concrete etching, etc.) - gives faster reaction & more obvious fizz.

Another way of testing is just soak the rock in question in your tank water for a week or 2, and test pH (+/- KH) before & after. If there is no change, you are set. <If you have hard water that is basically saturated, even "unsafe" rock (by the acid test) is fine as the rock can't dissolve into hard water .... but the soaking test will settle it for sure.>