I'm not really sure....but it may have something to do with the fact that the
iregular shape lets more bacteria grow in the substrate then in sand..so you get
nitrogen brakedown near the soil....not sure....but the reef-keepers tend to spout
about it all the time..and I do definately notice a difference in the crushed
coral tanks vs. my sand tanks....definately more growth....but who knows...it may
just be that my sand tanks are calcium limited or something.....

LeighMo wrote:

I kind of dissagree and kind of agree with you Leigh. Yeah, crushed coral and
coral
sand will bring up your PH...but this is not necessarilly a bad thing
(depending on
fish choices.)

Some people add crushed coral specifically to increase their pH. (I've done
the same with oyster shell.) But I don't do it any more. I prefer more
controllable methods. And I don't think it's a good idea for newbies.

Also, I prefer to use crushed coral mixed with sand for the same
reason that reef keepers are going away from it. The crushed coral tends to
become
a nitrate sink, which just happens to be good for plants..

Interesting. How does coral sand become a nitrate sink?

Leigh

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