coral

[fishdude]

is it safe to put in the tank. it's washed. as an ornament.

 

[CFC]

Yes but only for fish like livebearers and african rift valley cichlids or marine and brackish set ups.The calcium in the coral will raise the pH of the tank and increase hardness,crushed coral is often used as substrate in tanks containg the above mentioned fish.Barbs gouramis tetras and most other south american or far eastern fish will not appreciate it.

 

[mrV]

Corals, shells etc are mostly CaCO3. CaCO3 is almost insoluble into water, especially if the water is neutral or basic.

In soft/asidic water CaCO3 can dissolve, when there is enough CO2 in water and it dissolves CaCO3 (CO2 + H2O <=> H2CO3, H2CO3 -> HCO3- + H+, HCO3- -> CO3- + H+)

H2CO3 dissolves CaCO3. Then Ca2+ level increases (GH increases and also KH).

In my opion, it's quite unnatural to keep corals etc in freshwater tank.

 

[fishdude]

do you know how much it will raise it?

 

[Great Lakes]

Tough question. You can put it in and just keep track of your parameters making certain they stay in the healthy range for your fish.

 

[mrV]

It's impossible to say... It depends, how much H2CO3 is in water. Only small amount of CO2 will change to H2CO3 and H2CO3 also dissociates back to CO2 and H2O. And there is also other chemicals that affect too.

I think it doesn't change water values at all or not so much that you can measure changes. Best way is to use GH, pH -tests.