Rocks out in the front

[swivvr]

I have some stones in the front yard and really want to use them for my display tank, although I do not know if they are aquarium safe. I do not have something to test the rocks for any fizzing. Here are what they look like.

[Tammy]

I would also like to know if you can use stones that you have out on your walkway. And can you use driftwood it’s found land a pie off the rivers bank

[CT_]

I have a pile of rocks that look just like that in my yard.  I've used them to weigh down moss and for other things in my tank.  API test kit nitrate bottle 1 contains HCl and is strong enough to test rocks.

I boil the rocks before I use them but I don't think that's strictly necessary

[swivvr]

2 minutes ago, CT_ said:

I have a pile of rocks that look just like that in my yard.  I've used them to weigh down moss and for other things in my tank.  API test kit nitrate bottle 1 contains HCl and is strong enough to test rocks.

I boil the rocks before I use them but I don't think that's strictly necessary

How much drops should I add and will the rock fizz if its not safe?

[CT_]

one drop and a good eye is all you need.  fizzing is "bad" in the sense that the rock may dissolve and change you water parameters, which you should avoid doing unintentionally.

 

My default assumption is that river rocks have been in water long enough to wear round they also probably have anything that will dissolve out dissolved out by now.  But that's just an idiots opinion and not based on any evidence that I have.  #iamnotageologist

Edited February 18, 2021 by CT_

[Daniel]

I bet those are fine. They appear to be river gravel. I am a risk taker so I if it were me, I give it a try. Put them in some water, wait 24 hours and if the pH doesn't go up, then I would use them.

[Hobbit]

6 hours ago, Daniel said:

Put them in some water, wait 24 hours and if the pH doesn't go up, then I would use them.

Also put a glass of water next to them with nothing in it and test the pH. Because pH can go up if you let water sit out, regardless of whether rocks are in it. The key is to figure out if the rocks make the pH go up more.

[lefty o]

id use them. first id wash them off really good to ensure any pesticides/herbicides etc are off them.

[Schwack]

2 hours ago, lefty o said:

id use them. first id wash them off really good to ensure any pesticides/herbicides etc are off them.

I'm almost certain I ran into this with the first tank I set up. I used rocks from an old pond in my yard. Some were a bit porous, but I scrubbed and soaked them for a couple days to try and get any residue off. After I put them in the tank, I noticed changes to fish behavior within ~24 hours. At the time, my aquarium problem solving skills were in their nascent stage and I didn't connect the dots quickly enough to remove them ASAP. Lost two fish to that, but a big water change and removing the rocks cleared things right up. 

I've since used rocks from my yard again, but only after multiple scrubbings/soakings. I also avoid rocks with porosity like the plague. If I'm looking for swiss cheese rocks they'll come from my LFS or local wooded areas.

[morphy1701]

I think limestone (or rocks with a lot of lime stuck to them) are your biggest worry. IIRC, you can pour vinegar on rocks and if it fizzes you have limestone mineral deposits. And limestone will definitely dissolve and screw up your tank's ph. But those look like river rocks which should be fine. But I would thoroughly clean them first. Pretty sure fertilizer and pesticides are bad for fish!

[Will Billy]

The poor mans way of determining if they are calcareous rocks (meaning they are made of calcium) is to pour distilled white vinegar on them. I have rocks similar to that  in a water fountain. I didnt realize at the time that adding vinegar to kill bacteria and algae to keep my water fountain clean, was creating calcium deposits to build up in and around my fountain. It took me a bit to figure out what this hard white stuff was that was popping up in my fountain. After a bit of research the rocks i added to my fountain were calcareous rocks and the vinegar (although diluted) was slowly dissolving those rocks. Undiluted, distilled white vinegar reacts very quickly to the calcium in say limestone for example. If it fizzes it will change your water parameters. The biggest problem with calcareous rocks is that they will continually change your water parameters indefinitely until the rock is removed or completely dissolved. I have since converted to distilled water in my fountain with doses of 70% rubbing alcohol and hydrogen peroxide mixture to maintain a sterile environment for my indoor fountain, with no calcium build up. 

[Will Billy]

P.S. on a side note i realize the irony of simultaneously promoting life in my fish tank, and inhibiting it in my small table fountain. Never thought id play both sides of the field lol

[Lifeisgood]

Maybe I should look for calcareous rocks to buffer up my water.  I have been needing to use Wondershells because my plants were softening the water and my snails  shells were turning white.  Is this a thought worth pursuing?