Small rock from ocean safe for FW planted?l

[hb3133]

When on vacation to central California, my young daughter found a small rock washed upon the shore. It is 1"x1"x2", so very small and would fit perfectly in my 10 gallon fw planted tank. The rock is tan colored but I don't know what type. What are some of the concerns, if any and what precautions should I take? Any advice would be highly appreciate!

 

[Codefox]

I'd be very cautious...it is small it may not do much to your tank but I would bet that its a calcium rich rock and will leach into the water, altering your pH.

 

[mr funktastic]

boil the rock before putting it into the tank and do the vinegar test. pour vinegar or some other type of acid on it and watch to see if it bubbles. if it does then it is calcium rich and will leak, if not dissolve into your tank. if it doesnt then your good. just make sure u boil it to kill any remaining bacteria that is left in it.

 

[An t-iasg]

I wouldn't risk it, especially in a planted 10 gallon tank. It may be a small rock, but small tanks are more vulnerable to parameter swings, as you probably know. Do you use CO2? Do you know your KH and pH values now? The rock could possibly affect the KH and pH.

If you're really set on using it, put it in a bowl of water for a few weeks while you monitor the KH and pH of the bowl water to see if it causes a swing in those parameters.

 

[hb3133]

Thanks for all the great advice. I decided not to use it because the risk outweighs the reward. I'll just keep the rock in my daughters room and let her play with it.

 

[evercl92]

It's actually the CO3 (-2) that causes the pH shifts, rather than the calcium. It just happens to be that a large percentage of the rocks that contain CO3 (-2) also contain Ca (+2).... thus limestone. I'd agree that you probably shouldn't put the rock in your tank, especially if you have soft, acidic water. The acidic water will slowly dissolve the rock, increasing pH as well as increasing hardness (by release of the Ca ions). Neither of which is usually desirable for a planted tank.

 

[JDogg]

if it is well rounded and polished by the ocean it may not react very well with the acid test, if you wat to be sure i would take a nail of some othe sharp object ans scratch up the side that will be down in you tank, and then do the acid test.

 

[JDogg]

double post 8O