Calcium Rising without Dosing!!

Fin Jackson

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Hey everyone,
My calcium has been rising for a couple weeks now. I don't dose calcium yet, but I do dose KH. I check all my parameters 2 times a week and have noticed a massive increase in calcium even from the last test. I do a water change every Sunday arvo (just did one and checked parameters)

Values are compared below:

Wednesday Sunday
KH: 7.8 8.0

CA: 520ppm. 540ppm

MG: 1380 ppm. 1380ppm

No3: 4.25 4.2

Po4: 0.2 0.2

Temperature: 25 degrees Celsius

Salinity: 35ppt/34 psu/1.025 sg

I calibrate my kits when I get them and every few months. Did I calibration today and CA out by +25 ppm. Could it be the dry rock dissolving and releasing the CA into the water?
Any way to get it down apart from water changes would be appreciated.
Thanks Fin
 
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Shirak

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Hey everyone,
My calcium has been rising for a couple weeks now. I don't dose calcium yet, but I do dose KH. I check all my parameters 2 times a week and have noticed a massive increase in calcium even from the last test. I do a water change every Sunday arvo (just did one and checked parameters)

Values are compared below:

Wednesday Sunday
KH: 7.8 8.0

CA: 520ppm. 540ppm

MG: 1380 ppm. 1380ppm

No3: 4.25 4.2

Po4: 0.2 0.2

Temperature: 25 degrees Celsius

Salinity: 35ppt/34 psu/1.025 sg

I calibrate my kits when I get them and every few months. Did I calibration today and CA out by +25 ppm. Could it be the dry rock dissolving and releasing the CA into the water?
Any way to get it down apart from water changes would be appreciated.
Thanks Fin
What are you using to test Ca? My guess is +- 20ppm of the actual value is within the test error range of the kit. The Hanna is +-6% of the actual value so if you are looking at 500ppm Ca that could be +-30ppm which would return 470-530ppm reading. The other kits like salifert etc are probably even less accurate with a bigger range. I wouldn't stress it.

No I don't think your rock is dissolving.. pH would need to be really low for that to happen in any significant amount.

KH CaOH will add some calcium btw so yes you are dosing Ca in limited amounts.
 

Shirak

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Red sea is good but expect some slight variation in the results. Even if you do back to back tests on the same water you may not get exactly the same results. 20ppm for Ca is just a blip and 520-540 is nothing to be concerned about even if they are both correct.
 
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Fin Jackson

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Ok any suggestions on how to get it down apart from water changes as I'm already going to start doing 2 20 percent waterchanges each week.
 

Shirak

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What salt are you using? Some have elevated levels of things like Ca. What are you using for KH? I thought you were using kalkwasser but maybe not? Personally I would just do water changes at the recommended rate and not worry about Ca. How much Ca gets used will depend largely on what types of corals you are keeping and how heavily stocked the tank is. If you are not keeping many stony corals then Alk supplements and water changes would probably be fine for a long while.

I don't know any method to reduce Ca other than water change and/or let the tank inhabitants bring it down.
 

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There isn't really any way for only calcium to rise in a reef tank unless it is somehow being added. Tap water can be a significant source, but RO/DI at 0-1 ppm TDS is not a contributor. Are you by chance adding enhancers for coraline or soda ash to adjust PH ? This is one cause as would be false readings.
While your 500 range is not deadly, it is high. Dry rock especially aragonite Can Raise Calcium.
 
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Fin Jackson

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Ok thanks, I'll keep up the water changes and test the salt. It's quantum mixed reef salt, but at the moment I'm mainly keeping LPS as my tank is still stabilising before I try SPS. I started from aragonite. Anything I can do to lessen the effect?
Thanks all btw
 

Shirak

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Ok thanks, I'll keep up the water changes and test the salt. It's quantum mixed reef salt, but at the moment I'm mainly keeping LPS as my tank is still stabilising before I try SPS. I started from aragonite. Anything I can do to lessen the effect?
Thanks all btw
How long has it been running? Usually by the time bacteria and algae have populated the surface of the rock and sand you would stop seeing any rise in Ca from them. That should only take a few weeks. Are you stirring the sand up frequently? You also didn't mention the KH supplement. Ca could also be hidden in some other things like supplements for coralline etc.

According to the Quantum website the mixed reef probiotic salt should be around 430 Ca and 1295 Mg at 1.025sg. Your Mg is higher also. Makes me wonder if your salinity measuring device is a little off and it's reading on the low side which is giving you elevated Ca, Mg
 
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Fin Jackson

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Yeh I'ma look into getting a better testing system (probably automatic). I've found the the Red Sea magnesium is always overshooting the results saying that it's higher then it is.Im gonna try upgrade my salinity tester to a Milwaukee. Thanks guys for the responses.
 
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Fin Jackson

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No not recently. Last time was probably a month and a bit ago. If I calibrate it and it shows that it is to salty, would balancing the salinity help decrease the calcium concentration?
 
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Shirak

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No not recently. Last time was probably a month and a bit ago. If I calibrate it and it shows that it is to salty, would balancing the salinity help decrease the calcium concentration?
Lowering salinity will lower your Ca level yes. I think it would be a good idea to confirm your salinity. What kind of hydrometer are you using? Is there a local shop you can bring a sample for a salinity check with a calibrated device?
 
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Fin Jackson

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Yes I have just gone to my LFS and calibrated my hydrometer. It was tested against a calibrated Milwaukee, but the hydrometer measures in specific gravity, so accurate results are hard to get. It's not entirely accurate and is reading under the actual salt concentration. I have talked to people at the shop about picking up a Milwaukee, and a testing system soon and they highly recommend it. I'm am going to start correcting the salinity over the course of a week gently bringing it down to see if that works.

Thanks guys for all your help!
 

Shirak

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Yes I have just gone to my LFS and calibrated my hydrometer. It was tested against a calibrated Milwaukee, but the hydrometer measures in specific gravity, so accurate results are hard to get. It's not entirely accurate and is reading under the actual salt concentration. I have talked to people at the shop about picking up a Milwaukee, and a testing system soon and they highly recommend it. I'm am going to start correcting the salinity over the course of a week gently bringing it down to see if that works.

Thanks guys for all your help!
Personally I like a refractometer that I can check frequently against reference/calibration solution. Inexpensive swing arm hydrometer I used for years but I knew it was a off by a certain amount so I could make that adjustment on the reading. Otherwise it was very reliable in it's reading as long as I got all the bubbles off etc.
 

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Personally I like a refractometer that I can check frequently against reference/calibration solution. Inexpensive swing arm hydrometer I used for years but I knew it was a off by a certain amount so I could make that adjustment on the reading. Otherwise it was very reliable in it's reading as long as I got all the bubbles off etc.

I just went through this rodeo show. I would argue that all these methods are somewhat inaccurate except for Tropic Marin High-precision Hydrometer. I used this to figure out which of my salinity meters was telling the truth.

 

Randy Holmes-Farley

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I would argue that all these methods are somewhat inaccurate except for Tropic Marin High-precision Hydrometer. I used this to figure out which of my salinity meters was telling the truth.

Oceanographers generally use conductivity. The practical salinity scale (PSU) is actually defined by conductivity. Hydrometers (and refractometers) are mostly a hobbyist thing.
 
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