What could cause CA increase???

[duganderson]

My CA seemed to rise 30-40 PPM for no explained reason in my 28 g. mixed reef tank. I did not do a water change. I triple checked the CA rise with two kits (API and Salifert). I did not make any change except I started dosing Alk daily versus weekly.

Here are my numbers now...

CA 440
Alk 9 (api and Salifert)
Mag. 1280 (Salifert)

Any guess what could lead to a CA increase for me????

Thanks!

[blanden.adam]

Dosing, waterchanges, and testing errors are the only 3 possibilities. If it wasn't water changes, it was dosing or testing error, or some combination thereof.

[bertoni]

I agree that calcium can rise only if added. 30 ppm is getting down reasonable close to the accuracy limits of the test kits. The Salifert might be good to +-8 ppm if run very carefully.

[bnumair]

using any products like purple up?

[duganderson]

using any products like purple up?

no

Dosing, waterchanges, and testing errors are the only 3 possibilities. If it wasn't water changes, it was dosing or testing error, or some combination thereof.

Could dosing Alk daily versus weekly cause an increase in CA? (I'm guessing it would not).

If not, it must be testing error.

[barry_keith]

no



Could dosing Alk daily versus weekly cause an increase in CA? (I'm guessing it would not).

If not, it must be testing error.


Dosing alk, daily or weekly, will never increase calcium

[bertoni]

I agree. Dosing alkalinity cannot raise the calcium level of a tank.