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Is it time to start dosing calcium?

Mark...

Mark...

My mixed reef 180g is just over a year old now. I've been using kalk in the top off. On June 30th my Calcium was 390 and I added 32 tsp of BSR Calcium Chloride (based off BSR calculator) and the next day it was 430. Retested today (July 11) and it was 400 and I added 30 tsp of calcium chloride, and will retest tomorrow.

Should I continue doing it this way, or start dosing?

Thanks.
 
redfishbluefish

redfishbluefish

Officer Emeritus
Officer Emeritus
The question I have is, what's your alk? If kalk can't keep your calcium up, than your alk has got to be down there too. Test you alk as well....and if kalk can't keep both up (and that's what I suspect), than dose!
 
Mark...

Mark...

redfishbluefish said:
The question I have is, what's your alk? If kalk can't keep your calcium up, than your alk has got to be down there too. Test you alk as well....and if kalk can't keep both up (and that's what I suspect), than dose!
Click to expand...

On June 30th when Calcium was 390 alk was 9.01, will retest today.
 
saltkreep88

saltkreep88

NJRC Member
If your alk is still staying stable with kalk, I would just dose calcium twice a week so it is not such a big jump. Coral are not as sensitive to calcium changes as they are alk changes but a 40 ppm at one time is pushing it.
 
Mark...

Mark...

saltkreep88 said:
If your alk is still staying stable with kalk, I would just dose calcium twice a week so it is not such a big jump. Coral are not as sensitive to calcium changes as they are alk changes but a 40 ppm at one time is pushing it.
Click to expand...

Thanks for the info. I start doing it about 20 every 5 days.
 
downbeach

downbeach

Are you adding any type of pH buffer? The uptake of alk and Ca in any system, including normal calcification and abiotic precipitation is a ratio of 5 parts of Alk to every 2 parts of Ca, or 2.8dKH(50ppm) to every 20ppm of Ca. If you include the fact that there is less alk in reserve to begin with, it's very odd that you aren't seeing a similar scenario unless you're adding some other supplement.
 
Mark...

Mark...

downbeach said:
Are you adding any type of pH buffer? The uptake of alk and Ca in any system, including normal calcification and abiotic precipitation is a ratio of 5 parts of Alk to every 2 parts of Ca, or 2.8dKH(50ppm) to every 20ppm of Ca. If you include the fact that there is less alk in reserve to begin with, it's very odd that you aren't seeing a similar scenario unless you're adding some other supplement.
Click to expand...

Just topping off with kalk and bimonthly water changes. ph runs 7.9 - 8.1 range.
 
downbeach

downbeach

Mark... said:
Just topping off with kalk and bimonthly water changes. ph runs 7.9 - 8.1 range.
Click to expand...

[FONT=&quot]Saturated kalkwasser also contains this same ratio, @ ~ 800 ppm Ca(2pts.) to 2,000 ppm CaCO3(5pts.). It also has the added benefit of utilizing some of the CO2 in your system, which may help keep your pH in line. So, we still have the same dilemma, since using kalk is a good supplement of both your Ca and Alk, and in the proper ratio's. Have you double checked your test results with another kit, or another reefers kits?[/FONT]
 
saltkreep88

saltkreep88

NJRC Member
downbeach said:
[FONT=&quot]Saturated kalkwasser also contains this same ratio, @ ~ 800 ppm Ca(2pts.) to 2,000 ppm CaCO3(5pts.). It also has the added benefit of utilizing some of the CO2 in your system, which may help keep your pH in line. So, we still have the same dilemma, since using kalk is a good supplement of both your Ca and Alk, and in the proper ratio's. Have you double checked your test results with another kit, or another reefers kits?[/FONT]
Click to expand...
From what I have read other things can skew this even consumption such as coraline algae, bacteria from carbon dosing. My tank never had even consumption on kalk either
 
downbeach

downbeach

saltkreep88 said:
From what I have read other things can skew this even consumption such as coraline algae, bacteria from carbon dosing. My tank never had even consumption on kalk either
Click to expand...

This can be true, but it is almost always on the alkalinity side that there seems to be an excess demand, not the Ca side. One example would be where some animals will incorporate a cetain amount of Magnesium or Strontium in place of Ca, changing the ratio to ~ 18 ppm Ca to 50 ppm alk, using less Ca in relation to Alk. You may also see a small alkalinity decline in the nitrogen cycle, i.e. carbon dosing, but again its the alkalinity that is declining not the Ca. This leaves us with the WC's, and/or testing.
I would suggest if you're ready to start dosing, to make sure your SG is accurate when you make up your WC water(using RO/DI water), since this is where you're adding your Ca, Mg and alk to begin with. I would not rely on a swing arm type hydrometer for this; a properly calibrated device, i.e. refractometer would be a better choice, and keep a regular schedule of WC's in both frequency and volume. Use your two part additive(s) to get your numbers where you want them(testing), and start to monitor/record your uptake over a few days to a week. Use this calculator fill in the blanks for your system, select the two part you are using from the drop down menu to get your doseage. By dividing the dose by the number of days you were recording you will get your daily dose. It is also possible that you may only have to dose the alk part for a while, with the WC's keeping up with your Ca and Mg demands.
 
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