Noraml ?

[Quis]

I post this in the reef forum, but I think this might be the right one.

Is it normal for my alkalinity to drop from 10dkh to7dkh everyday. My tank is about 70% sps with the other 30% being lps, and zoo's. My calcium only drop about 10-15ppm in the same time frame. I have to dose about 120mil of backing soda a day over a 5 hr period to bring it back up to 10 dkh. I'm using Tropic marin salt if that helps. Thanks for your help.

Cal - 420
Alk - 10dkh -7dkh
Nitrate - 0
Pos - 0
Sg - 1.026
Temp - 78-80

[Maudsley]

What is your Mg? If this is not in parameters your alk and Ca will drop alot faster and be less stable

[Quis]

I'm not sure what my Mg level is. I have never check for it or add any Mg sup. If my Mg is indeed low shouldn't my cal drop just as fast as my alk?
P.S. I also drip limewater 24/7 if that helps.

[bertoni]

For every 20 ppm of calcium consumed, the tank's alkalinity will drop by about 2.8 dKH, which is consistent with your numbers. That rate of drop isn't all that surprising, but a magnesium test might be useful.

[Quis]

I guess I'll go ahead and buy a Mg test kit just to make sure my Mg level is correct.