July, Solid CaCO3 Article

[DBW]

Randy,

In regard to this comment in your article "CHEMISTRY AND THE AQUARIUM", July 2002 ....

"Why not just measure calcium and alkalinity in the water before and after addition of solid CaCO3?"

Have you considered (for interest to see what the difference actually can be) centrifuging a water sample in the aquarium after addition of the calcium carbonate powder to get access to the actual dissolved calcium carbonate level?

 

[DBW]

And another one re the use of calcium carbonate substrate in your evaporation top up water .... what about biofilm development on the grains?

 

[randy holmes-farley]

Good points.

No, I haven't tried centrifugation, but I'm sure it would work if someone had an appropriate centrifuge and wanted to go to the effort.

Some sort of biofilm would certainly develop on the grains. Whether that would inhibit dissolution to the point where it no longer worked satisfactorily I cannot say. I do a similar thing with calcium hydroxide and biofilms are not too much of a problem, but the pH is higher there and that may reduce the formation of a biofilm substantially.

 

[DBW]

Randy,

Yes, that was my thinking too. Since the pH conditions of the water in contact with the calcium carbonate is not as extreme as calcium hydroxide there might be some bacteria that can grow in there. I suppose the test is if someone has done this for a significant length of time and noticed any drop in the pH or the formation of a film of some sort.

Anyone done this yet?