Is this a normal thing??

[NoSchwag]

I have 6 clams, 1 of them is very very big and 30 or so SPS frags and 1 colony.

I am not using much ca. at all.

My mg is at 1300, alk is about 10, po4 is 0, nitrate is .02 (no macro algea)

what's up with this?

 

[Randy Holmes-Farley]

What exactly are you adding?

What salt mix?

Are the frags growing rapidly?

 

[NoSchwag]

I mean i'm not sure what rapidly is.. I can tell you that my stylo has healed over the dead parts, and my slimer has encrusted in a few weeks.

I'm asking is my low ca. demand unusual seeing as I have a huge clam. I thought they used up a lot of ca.?

I'm using IO, the ca. of the makeup water is about 380.

 

[Randy Holmes-Farley]

Corals and clams use calcium and alkalinity to deposit calcium carbonate skeletons and shells. Calcium drops far more slowly, on a percentage basis, than does alkalinity.

If you are not supplementing alkalinity, then you would not expect to need to supplement calcium. If alkalinity is too low, then they will not be able to calcify at all. Have you measured alkalinity?

 

[NoSchwag]

just tested.. 3.42 meg/L

 

[Randy Holmes-Farley]

I'd just watch it over time.

 

[74nautique]

Randy, not to change the subject but I was wondering if 8-9 meg/l of Alk is too high?

 

[Randy Holmes-Farley]

You sure you do not mean 8-9 dKH?

I recommend 2.5-4 meq/L, which is 7-11 dKH or 125-200 ppm CaCO3 equivalents.