Sea Shells

[PattyAnderson]

Does anyone know if it would be ok to put sea shell in a fresh water tank?

 

[LyraGuppi]

Shells will affect the gH and pH, making the water harder and more alkaline. (I've never ran before and after tests on my shellie tank, so I can't say how much they change the water) This is good for some fish, but soft water fish won't appreciate it.

 

[StevenF]

Sea shells and fresh water shells are made of calcium carbonate and magnesium carbonate.  Plants and invertebrates need calcium and magnessium to live.  Rivers and lakes typicaly have some calcium and magnessium carbonate in the water.
 
If the shell is put into a container of DI water the Gh will go to about 20-25ppm and the KH will go to about 50ppm.  Due to the limited solubility of of calcium and magnessium carbonate the effect on GH and KH will never exceed these values. I am using RO water in my tank and it has snail shells in it.  After I fertilize it the GH is consistently about 25ppm and KH 60. normally RO water out of the tap has GH of about 0 and kh of 0.   it doesn't have a significant effect on GH  and the affect on KH will help stabilize PH.  
 
Sea shells are perfectly safe to add to the aquarium as long as you first wash them with fresh water first to remove any salt.  Depending on the hardness and PH of your water a typical shells will lat a year or many years.  

 

[julielynn47]

I don't know anything about the water parameters but I know that they will start to break down.  I know because years ago, when I didn't know diddly squat about aquariums, I put them in mine.  I had collected them from the beach. They were all shiny and pretty....were...they started to break down and got chalky, lost all their shine.  

 

[PattyAnderson]

I put a large on in I found at the beach, after I rinsed it in a colander really well. My water clouded up so I thought that may be the culpret. I removed it and did a water change and it has stayed clear. I have guppies and platy's. Thanks for the input!

 

[Vindicare066]

Out of curiosity how large is your tank? And how large is the shell? The larger the shell, the more surface area there is to react and dissolve into the water, so if you have a small tank and a large conch shell, this could lead to high levels of GH and pH so be mindful of this.  The shell probably caused the cloud you described, I would recommend you boil the shell and then letting it soak in a warm bath for a while, that should kill any bacteria that is remaining on the shell. 
 
Cheers

 

[PattyAnderson]

Thanks, I think I will just leave it out. My tank in 30 gallons, and the shell is a large one, but I think I'll use it in the bathroom instead.

 

[StevenF]

The size of the shell and tank will not affect the GH, kh or PH.  The reason for this is that one liter of water can only dissolve about 11 mgram or calcium carbonate and 11 mgram of magnesium carbonate.  At these levels the water is saturated with these materials and no more will  dissolve.  
 
To get get a higher GH you would need to add calcium or magnesium sulfates, nitrates, or chlorides.  Far more of these will dissolve in the water than carbonates.  That means sulfates, nitrates, and chlorides are responsible for most hard water and high GH readings. High levels of KH or PH is mainly caused by elevated levels of sodium or potassium in the tank.  Calcium and magnesium carbonate have a very limited effect on Kh and PH.  
 
Due to the limited solubility of calcium and magnesium carbonate the absolute maximum levels you will see in pure water is 25ppm GH, 60ppm KH, and about 7PH.  Anything more than that is caused by something else in the water.