Calcium Dosing... How long?

I've been dosing Kent's A-B for calcium (according to instructions) for about 2 1/2 weeks now.  When I started, my tank was a shocking 240.  Now, even though I've dosed every day and double-dosed a few times, I'm still only up to 300.  What's up? 

Alkalinity and Calcium are continually used by almost every animal in the tank. Dosing must keep up with that use. I have never understood why the manufacturers even bother to give a recommended dosage, since it all depends on the amount of animals using it in any particular tank. Testing the levels and increasing or decreasing the dosage amount is the ONLY way Alk and Ca additives should used. Dose as much as is needed to keep Alk and Ca at the desired level.

I've used this site on a past tank that I was having the same issue with. Very useful.

http://reef.diesyst.com/chemcalc/chem_calc3.html

Hold on.
Before doing anything else, the Alkalinity level must be known. That has a lot to do with the reason for Ca being hard to raise. The Mg level can also be an issue. You said the Ca is at 300 ppm. What are the Alk and Mg levels?

Are you dosing both parts and in what proportions, equally or no? Regarding dosing, yes, maintenance at a higher level requires less additive than getting there.

The levels of Alk and Ca vary by tank and it's not necessary to keep one tank levels the same as another. Just keep them within range.

That's the beauty of using Baking soda and Calcium Chloride. Inexpensive, easy to mix up and easy to add. Eventually, if the tank is using a couple liters of each solution weekly, it's time to consider a Calcium Reactor.


Edited by Mark Peterson - November 08 2010 at 8:16am

A 2 part like that is used to maintain levels. Only add calcium right now and just watch alk, if alk drops add a little bit. I never follow the dosing guides

I don't know what you mean by " 2 cups of RO water-Calcium Solution"

Oh, sorry. I forgot you are using the Kent liquid two part solutions.
I was trying to fully describe the homemade liquid Calcium solution, to be sure you knew "2 cups of what?"

The problem caused by too much Alk has to do with coral and sensitive fish parts like gills getting "burned". This can lead to slow death. An Alk of 20 and dropping isn't bad enough to be concerned about.

Calcium can be "dumped" in without causing any bad effects. That's why I said 2 cups. But since the Alk is dropping and is now below 20 (with that 60 ml you added), you can keep adding and checking. You are doing well.

Now that you know to add only the component that is needed(Alk, or Ca, or Mg, or etc.), you have passed an important milestone in your understanding of reef chemistry.

You weren't dumb. My remark is why would the manufacturer be so dumb with their instructions!

At one point in this hobby, I didn't dose anything and didn't do water changes for 18 months. I couldn't keep Hermits alive and thought the Sixline was killing them so I got rid of the fish. That was dumb. 
Soon after, I found out about Alk and Ca and my life was changed forever.  

Another recommendation would be to check out some Alk/Ca/Mg dosing guides.  Or even check out Bulkreefsupply.com.