Freshwater rocks.

[petitemonk]

Hey hey Hey, I was wondeting if there is a guide as to what rocks can be used in a fresh water tank. or if anyone has any tips. Like can i use a rock thats on the ground and just put it in my tank.

 

[QTOFFER]

You want rocks that are inert and contain no metal - copper and iron ores are out!
Granite, slate, petrified wood, and most sandstones are OK.
Limestone and marble will react in water and raise pH - you can test with muriatic acid - if the rock bubbles, it shouldn't be used.
Any rocks (even if purchased in the lfs) should be washed well. Rocks from outside should be washed with boiled, and rinsed many times.

 

[petitemonk]

Many Thanks : )

 

[deeni0z]

If you don't have any muriatic acid, could a control scenario be used? For example, I have a rock, don't know what type it is. I use RO water which I know *for sure* is 7.0. I then leave it over night and check the pH. Is that a good indicator for limestone/anything other than ores?

 

[Scottcenfla]

QTOFFER hit it right on. Not sure if a overnight dip with a rock will give a accurate reading or not. Limestone probably won't effect the PH overnight in a rock form vs. powder, but it will over time.

 

[trent]

i was always told not to put any old rocks in your aquarium. that you should buy rocks sold for your aquarium. i found it to be quite expensive at a lfs for this kind of rock for filling larger tanks, and shipping would be insane for some rocks. so i took rock from river bottom, scrubbed them good, and soaked them for about 2 weeks. i had a regular (hang on back) filter in the bucket and did regular water checks. when it seemed to be all good, i transferred to my tanks. ive never had a problem with any fish.

 

[QTOFFER]

You can buy muriatic acid (30% hydrochloric acid) at a paint or hardware store.
Some people suggest vinegar as an indicator, but because it only contains 5% acid, it may not do the job as well.