Rock question

[Bobby2415]

I’m looking to add larger rocks to my aquarium and I was hoping not to spend an arm and a leg getting it from my lfs. I currently have a large amount of I believe dolomite and sandstone rock where I live. I was just wondering if anyone has had any experience putting that kind of rocks in your aquarium. I’m under the impression it could raise the ph in the tank. I currently have primarily Central American cichlids in my tank and the ph is 7. Thanks!

 

[FJB]

Dolomite is a carbonate, including calcium and magnesium. It would raise the pH, particularly if you are now at 7 (neutral). You may be better off with inert rocks (igneus). Sandstone may be ok, depending of the type, but some are also carbonate based. Any carbonate based material will raise the pH if currently at 7 or below.

 

[deeda]

You can also try putting the dolomite into a bucket of your tap water (after dechlor if needed) and test the pH, hardness and alkalinity to see if it changes over the course of a week. It may be helpful to add an air stone to the bucket below the rocks if you have one.

Are you sure your pH is just 7? What test kit are you using? Is the pH the same for your tap water both immediately drawn from the tap and then after a 24 hour off gassing?

 

[TheWolfman]

There’s a way to tell if rocks will alter ph or not. I’m really not too familiar with it though. Something alone the lines of dropping a liquid on the rock and if it fizzes up it’s not inert and will alter ph. Sorry I can’t be more help.

 

[islandguy11]

There’s a way to tell if rocks will alter ph or not. I’m really not too familiar with it though. Something alone the lines of dropping a liquid on the rock and if it fizzes up it’s not inert and will alter ph. Sorry I can’t be more help.

Yep, just ordinary household vinegar can be used as you say.

 

[Zanzag]

I believe the other thing people use to test is muriatic acid

 

[Bobby2415]

You can also try putting the dolomite into a bucket of your tap water (after dechlor if needed) and test the pH, hardness and alkalinity to see if it changes over the course of a week. It may be helpful to add an air stone to the bucket below the rocks if you have one.

Are you sure your pH is just 7? What test kit are you using? Is the pH the same for your tap water both immediately drawn from the tap and then after a 24 hour off gassing?

I will try the bucket method you speak of. Sounds like a good idea. I use the API master test kit and the water from the fish tank now is 7. Any idea how much it would raise the ph? Enough the negatively effect Central American cichlids?

 

[TheWolfman]

If you testing the water make sure to test kh and gh as well.

 

[Bobby2415]

If you testing the water make sure to test kh and gh as well.

How do I test for that?

 

[kingthedog]

I believe the other thing people use to test is muriatic acid

but you have to be very careful with muriatic acid