Rocks for the aquarium

[Raven]

I am setting up my 90g aquarium for some African Cichlids and I have to buy or find rocks for it. I do not want to buy them from a pet store, because it would end up costing more then what the tank was worth, so I would like to use some that I can find or dig up. I was wondering if there is a way that I can test the rocks, to know if they are safe to use in the aquarium? Also what type of rocks should I look for if I have to buy some?

 

[Menagerie]

The only free rock in my 80 gal Mbuna tank is basalt that my fiance found. The rest is lace rock that we paid for--it was and still is worth every penny (all 30000+ pennies BTW, we did not buy all of the rock at once). I love the way it looks. The other great thing is it tends to crumble if it hits the side of the tank, unlike the basalt (it's amazing I haven't cracked the tank ). I do take all the rock out on a fairly regular basis to clean the gravel.
I find that flat rocks are just not as easy to build up for caves and hiding holes. On the other hand, I use round river stones in my bricardi tank and when they excavated around the stones, the piles fell (no one was injured, as this occurred over a period of days).

I was wondering if there is a way that I can test the rocks, to know if they are safe to use in the aquarium?

There is an acid test. The mild version involves vinegar (I think) if it fizzes don't use the rock. There is another test with a stronger acid, but I can't think of it.

 

[Annie]

For my cichlid tank, I went to Home Depot and got this huge piece of slate that was about $4-$6 and hammered and chiseled pieces off. Then on the sharped edges I had to sand them down so they were rounded.

 

[youronlysin]

In another thread, I believe someone mentioned that you could use Muriatic acid in the same fashion as the vinegar. Be careful with that, though. You can find it in most hardware stores......it is often used to clean driveways and concrete.

 

[Menagerie]

Muriatic acid

Yes! That was the name I forgot!

 

[krap101]

was it labeled as slate? and how can you tell the difference between slate, sandstone etc? because theres this rock place that labeled them as flatrock or something and i dont want sandstone because itll decompose (i know not the right word but you get the idea) and... yeah. ill try and stop by homedepot sometime . my mom likes the plants there and so do i. we bought this really nice hanging plant there and 2 japanese cherry trees there. their 50% off right now originally 70$ and we payed 35 and we got 2 .

home depot rocks!!

 

[PhilMar]

I would really like to know more about the acid test. We bought our house from a Geologist, and my back yard is full of all kinds of strange rocks left over from him that would look really good in my 50 Gal tank. I've been a little unsure about adding any of them to my tank.

any ideas would be appreciated

 

[krap101]

the acid test tests how much it'll affect your ph/hardness. when you put an acid (vingar/muriatic acid) when it bubbles then thats usually bad unless you have like a rift lake cichlid or something.

maybe someone else can explain it better

 

[PhilMar]

Is that the only thing I need to worry about, ph/hardness? There's no telling where some of these rocks have come from.

 

[dsmalls]

For just 'regular' backyard rocks, just rinse 'em off, maybe a little bleach, rinse, and drop them in. I get rocks all the time from down at the creek and haven't had one problem. My fish and newts seem to enjoy the landscape. Slate and all those other 'exotic' rocks, I'm not sure about.

 

[Menagerie]

Is that the only thing I need to worry about, ph/hardness? There's no telling where some of these rocks have come from.

Unless you are concerned that there are parasites or bacteria on the rock, the only thing it will do is alter your ph and/or hardness. Some rock will disintegrate over time (the Utan Ice rock comes to mind). The acid test is simply, if the acid on the rock fizzes, then the rock will alter your ph and/or hardness.

 

[jratuszn]

I got all of the rock for my tank at a landscping place. $0.30/lb, instead of $4/lb at the lfs. It sit outside usually, so you'll prolly need to wash it really well before putting it in your tank. I baked mine in the oven overnight to sterilize them, as an additional precaution. Well worth the extra work, for the money you'll save, tho.

-J