sandbed/calcium

[fullkontact]

I had very high calcium levels, maybe due to low alkalinity? anyway, I have restored alkalinity to 5 meq/l, ph is about 8.2. My calcium is slowly coming down and is now around 600ppm. My question is why is the surface of my sand starting to solidify? if I disturb it, it comes up in chunks(just the surface). The only other thing that may be of interest is I have a diatom problem, or maybe it is dinoflagellates.

 

[fullkontact]

anyone?

 

[Pandora]

fulk: I think this article will answer most of your ca/alkalinity q's:
http://www.reefkeeping.com/issues/2002-04/rhf/feature/index.php

With the solidifying effect, I'm not sure, but I think it could be unrelated to the other (I was thinking at first it was calcium or another mineral precipitating, but uncertain about that). Sometimes algae that isn't fully grown isn't easy to see, but can cause your sand to stick together (would explain why it's just the surface).

 

[bertoni]

The alkalinity and Ca should be no higher than about 4.0 meq/L and 450 ppm, respectively. You can replace the sand that's turning into chunks.