ca monitor

[joelsaxton]

Well, I decided to test the water again this evening. I put the probe in and got a reading of 0. This was pretty strange, so I decided to calibrate the probe. I left the probe in the 100ppm fluid for quite a while until it begain flashing 5 or 6 times, so I hit enter and get the "Err" message that I kept getting on the first Ca probe I had. Perhaps this is just a strange coincidence, but this is 2 out of 2 probes that seem to be behaving defectively. I am going to let it sit in 100ppm fluid and try to calibrate it again later.

[drjrose]

Originally posted by loudell
In my experience most reef hobbists are more fastidious than most pharmacists.

I think not.

[drjrose]

I have been using my meter since about 10 Feb. I have tried calibrating it and then using it for about a week on a daily basis. My Ca was falling from about 375 to 225 over two days or so. Like and idiot I believed the readings and dosed Ca. Tonight I checked with the Salifert kit and got about 650 based on extrapolation since the kit only goes to 500 on regular dilution. I have turned to this thread, and read it all, for answers.

I am going to have to change my procedures to the three glass method, all the same temperature and no more testing directly from the tank/sump. I do keep the probe in the 100 solution as directed.

I ordered more calibration solutions about 2 weeks ago, but they have yet to arrive. It would be useful if these solutions came in bigger bottles - at least 100 cc.

[Randy Holmes-Farley]

My Ca was falling from about 375 to 225 over two days or so.

As you discovered, that never happens unless you add a huge amount of buffer to precipitate CaCO3. Otherwise, there is no place for it to go.

[SEAREEF]

mine is still working great ,a little drift,but not much

[gbr]

seareef, what's a little? Has Salifert changed?

I talked to Lou at AmericanMarine and he is sending me a new probe tip so once I get that I will be able to continue testing mine.

[SEAREEF]

gbr ,yes my salifert is still pretty right on ,this time when u get your new probe ,I would soak it in tap water for at least 5 hrs .Never submerge the whole probe ,And be gentle with it ...........I dont understand why all u guys are needing new tips

[drjrose]

Originally posted by Randy Holmes-Farley
My Ca was falling from about 375 to 225 over two days or so.

As you discovered, that never happens unless you add a huge amount of buffer to precipitate CaCO3. Otherwise, there is no place for it to go.

I am doing my regular water change this weekend so the Ca should come down some. Is there any physiologic threat to my tank due to this high Ca? There has been no precipitation. pH currently ranges from 8.10 to 8.25 and is regulated by kalk dosing on an Octopus controller (recalibrated last night). I realize that the kalk will continue to add Ca.

Is there any reliable way to boost the metabolic consumption of Ca? Would Coral Vital help in this regard?

[Randy Holmes-Farley]

Is there any physiologic threat to my tank due to this high Ca?

I do not know for sure, but I don't think there are many undesirable biological effects of somewhat elevated calcium as long as the alkalinity is OK.

I do not know what is in coral vital, so it is hard to say what benefit, if any, it has. Calcium consumption is speeded by normal to high alkalinity and pH, and normal (maybe high) magnesium levels.

[nyfireman3097]

i have my Cal at 500 alk 7 and mag 1450
Nick

[SEAREEF]

cal too high is a big no no

[nyfireman3097]

y?
Nick

[SEAREEF]

im not sure ,i just know when ever i see a tank with readings over 500 ,which is often .corals arnt doing well as far as opening .as a rule of thumb i never keep cal over 475 if i can help it ...

[SEAREEF]

Nick ,i think a good range for your dkh should be 10-12 ,i mostly have sps and i try to keep mine at 12- 13

[Randy Holmes-Farley]

cal too high is a big no no

I don't tend to agree, but I welcome the opinion.

[SEAREEF]

Randy
I relize you are a chemist,and im sure you know much more than me about this but
my opinion is i would never personally run a system like mine with a cal over 500 ,i have tryed it before with neg results,
heres where i try to run my system

salinty 1025- 1026
cal 425-450
mag1400
dkh 13
iodine .06
with a grip of light

[Randy Holmes-Farley]

Well, FWIW, lots of folks have run nice reef aquaria in the 450-550 ppm calcium range. I certainly agree that aiming for lower values is a fine idea. I usually recommend 380-450 ppm.

[SEAREEF]

randy
i agree with you ,550 may be cool its just right on the line
lol

[Randy Holmes-Farley]

Happy reefing.

[galleon]

Originally posted by Randy Holmes-Farley
Is there any physiologic threat to my tank due to this high Ca?

I do not know for sure, but I don't think there are many undesirable biological effects of somewhat elevated calcium as long as the alkalinity is OK.

I agree with the above. I would think the only drawback to such elevated calcium is that the coral may have to dedicate more energy to regulating intracellular Ca++ concentrations. One way this is accomplished in corals is by forming coordination compounds with organic ligands, which may be expensive to make.

[Nate58]

Personally, I run calcium at 500 to 550. Coral growth is doing well. The downfall that I find is the calcium buildup around impellers. Once a month I have to dump the impellers in vinegar to clean them up. I let one pump go for three months and the impeller welded itself to the pump.

[Nate58]

Personally, I run calcium at 500 to 550. Coral growth is doing well. The downfall that I find is the calcium buildup around impellers. Once a month I have to dump the impellers in vinegar to clean them up. I let one pump go for three months and the impeller welded itself to the pump.

[Nate58]

sorry for the doulble post

[ATJ]

Gattuso et al. (1998) found that increasing calcium and alkalinity to 1.5 times normal levels did not increase calcification rates, but it also didn't decrease them, which suggests that elevated levels of calcium (at least in the 500-600 mg/L range) is not detrimental to corals. Lowering the calcium concentration below around 300 mg/L did decrease the calcification rate.

While an elevated calcium concentration appears to do no harm, it also provides no benefit and it is much easier (and cheaper) to maintain calcium at around natural seawater levels.

Note that normal seawater has a aragonite saturation of 350-400%.

Gattuso J.P., Frankignoulle M., Bourge I., Romaine S. and Buddemeier R.W. 1998. Effect of calcium carbonate saturation of seawater on coral calcification. Global and Planetary Change.18(1-2):37-46.

Abstract: The carbonate chemistry of seawater is usually not considered to be an important factor influencing calcium-carbonate-precipitation by corals because surface seawater is supersaturated with respect to aragonite. Recent reports, however, suggest that it could play a major role in the evolution and biogeography of recent corals. We investigated the calcification rates of five colonies of the zooxanthellate coral Stylophora pistillata in synthetic seawater using the alkalinity anomaly technique. Changes in aragonite saturation from 98% to 585% were obtained by manipulating the calcium concentration. The results show a nonlinear increase in calcification rate as a function of aragonite saturation level. Calcification increases nearly 3-fold when aragonite saturation increases from 98% to 390%, i.e., close to the typical present saturation state of tropical seawater. There is no further increase of calcification at saturation values above this threshold. Preliminary data suggest that another coral species, Acropora sp., displays a similar behaviour. These experimental results suggest: (1) that the rate of calcification does not change significantly within the range of saturation levels corresponding to the last glacial-interglacial. cycle, and (2) that it may decrease significantly in the future as a result of the decrease in the saturation level due to anthropogenic release of CO₂ into the atmosphere. Experimental studies that control environmental conditions and seawater composition provide unique opportunities to unravel the response of corals to global environmental changes.

[Randy Holmes-Farley]

Thanks.

My understanding from other studies as well is that alkalinity is limiting at NSW levels. IMO, an interesting open question is whether calcium has become limiting when the alkalinity is pushed to 4 meq/l or higher.