Calcium 500/dkh 7 why?

[JRod]

My uncle has a 190 that has been running for 2 years now.

He has a calcium reactor and had a question.

His calcium is 500 and dkh is only 7, and he is wondering why its so low.

His readings are:

eff 6.8
ph 7.7
Nitri/Nitra 0
Temp 77


Any ideas.

Thanks.

Joe

 

[bertoni]

http://www.reefkeeping.com/issues/2004-12/rhf/index.php

That article talks about how calcium and alkalinity can get out of balance. Also, some salts are a bit out of balance out of the bag.

A one-time shot of baking soda could get the alkalinity up without changing calcium. This calculator will tell how much is needed if given the target dKH and the water column size:

http://home.comcast.net/~jdieck1/chem_calc3.html

 

[JRod]

Thanks.

Will forward to him to give a look.

Joe

 

[Randy Holmes-Farley]

The reactor will add calcium and alkalinity in about the proper ratio that corals use it, but if the starting salt mix is not correct (like Oceanic that has excessive calcium), then the reactor cannot account for that.

There are also other reasons why the calcium and alkalinity may drift long term, and many of them are in the first linked article above.

If he wants to raise alkalinity, either he can add more CO2 to the reactor (which will only boost calcium by 20 ppm for each 2.8 dKH rise in alkalinity), or he can boost it with something like baking soda.

 

[JRod]

Appreciate the help.

Joe

 

[Randy Holmes-Farley]

You're welcome.

Good luck.