What testing kits or devices do you recommend for Calcium?

[threebuoys]

I just received my first ATI water test report for a 1 year old tank and discovered my calcium was at 520 which is considerably higer than the 440 I calculated using an API kit. I had added calcium chloride a week befor the water sample to raise the levels up from 360, not realizing the test kit was reading significantly below actual.

My alkalinity test using the Hanna Checker (HI772 checker) also gave me a much different reading than the ATI test. 7.83 for ATI and 8.40 for Hanna. Not sure what's going on here either.

So, before I continue with any tyoe pf dosing, I need to get control of my measuring devices.

Any suggestions?

 

[Snoopy 67]

Many like me use Salifert.
Their alk kit tests in shades of pink, very hard for me to get it right so I went with NYOS in yellow & much better although spread out a little more in values.

 

[Righteous]

I’d trust the calcium reading since that is measured by ICP. Alkalinity can’t be measured by ICP so they are using an alternative method, possible a test kit.

My biggest advice is always use fresh test kit reagents and also clean your test tubes and cuvettes really well.

Hanna is usually fairly consistent with alkalinity, again just make sure you have fresh reagent. Salifert is a decent calcium kit as well, I find it usually around +/-20ppm. The Hanna calcium checker is more consistent in my opinion, but it is very difficult to use and requires a lot of diligence.

 

[Spare time]

I use the red sea calcium test

 

[Kingston]

I use salifert for calcium. I also just got my ATI ICP results back and they seem close. 460 salifert and 455.8 ATI.

 

[Rick Mathew]

I just received my first ATI water test report for a 1 year old tank and discovered my calcium was at 520 which is considerably higer than the 440 I calculated using an API kit. I had added calcium chloride a week befor the water sample to raise the levels up from 360, not realizing the test kit was reading significantly below actual.

My alkalinity test using the Hanna Checker (HI772 checker) also gave me a much different reading than the ATI test. 7.83 for ATI and 8.40 for Hanna. Not sure what's going on here either.

So, before I continue with any tyoe pf dosing, I need to get control of my measuring devices.

Any suggestions?

Yes @threebuoys this is a dilemma that many find themselves in...Which one is correct?? @Righteous has some good advice...clean lab equipment and reagent that has not expired are good starts. I wrote 4 articles on the very subject of testing that focus on the very questions you are asking and more. They are titled "GETTING IT RIGHT" ...you can fide all of them here https://www.reef2reef.com/ams/authors/rick-mathew.66447/

It is very smart to halt your dosing until you get some clarity to your measurement values. Here are a couple of things that you can do to help to clarify the results.

1) Make multiple measurements with your test kit to get an idea of how repeatable your results are...I suggest at least 3...5 is better. If the variability is high > 10% you will need to work to discover why. The articles can give you some ideas where to look.

2) Get a different test kit (you will get lots of suggestions) and run a comparison to your current kit...Same procedure 3-5 sample measurements and look at the variation and compare the variation and the avg measurement to you API kit

3) Have someone else test your water and see where their results fall...

It is important to note that ICP results are not always totally accurate. They have variability and errors in their tests as well...

As for the Hanna Instrument HI 772...I have found this to be very accurate and repeatable and if you are using fresh reagent and clean equipment I would have a high degree of confidence in the results...That being said it would not hurt to validate your measurement .

Let me know how it goes

Rick

 

[threebuoys]

@Randy Holmes-Farley

I just received my first ATI water test report for a 1 year old tank and discovered my calcium was at 520 which is considerably higer than the 440 I calculated using an API kit. I had added calcium chloride a week befor the water sample to raise the levels up from 360, not realizing the test kit was reading significantly below actual.

My alkalinity test using the Hanna Checker (HI772 checker) also gave me a much different reading than the ATI test. 7.83 for ATI and 8.40 for Hanna. Not sure what's going on here either.

So, before I continue with any tyoe pf dosing, I need to get control of my measuring devices.

Any suggestions?

Do you have a suggestion for a calcium test kit? And, how should I approach the discrepancy for alkalinity?

Thanks for any insight you can offer.

David

 

[DivingTheWorld]

Salifert for Calcium.

If you are confident in your high Alk measurement, simply stopping or reducing Dosing will allow it to naturally lower.

 

[threebuoys]

Salifert for Calcium.

If you are confident in your high Alk measurement, simply stopping or reducing Dosing will allow it to naturally lower.

The issue with Alk for me is how to get confident in either number since they are so different. The Hanna Checker and reagents are only 2 months old, and I'm confident I followed the instructions correctly. On the other hand, customers of professional labs have to have a high degree of confidence in their tests also.

So, have other hobbyists had similar discrepancies and how did they resolve them seems to be a relevant question.
Try a third test kit for Alk, who knows what I'll see?

 

[blaxsun]

Red Sea and Hanna for me. They’re usually really close to each other (+/-10-20ppm).

 

[arking_mark]

As several people have mentioned, hobby-grade test kits aren't particularly accurate. Personally, I use Hanna, but just for ballpark measurements and trends. In my unscientific assessment, Hanna Ca is no better than +/ - 50ppm. Hence I dose balanced Ca/Alk. However, since Ca/Alk isn't quite perfectly balanced consumption in my tank, I use ICP testing and make corrections every 6 months to a year.

How to balance Ca/Alk in the reef aquarium?

After reading: http://www.reefkeeping.com/issues/2004-12/rhf/ Here are my takeaways: For most practical purposes, Ca and Alk are consumed equally. However, "...the demand for calcium and alkalinity may not be precisely balanced at 20 ppm calcium per 1 meq/l of alkalinity..." The biggest...

www.reef2reef.com

 

[threebuoys]

As several people have mentioned, hobby-grade test kits aren't particularly accurate. Personally, I use Hanna, but just for ballpark measurements and trends. In my unscientific assessment, Hanna Ca is no better than +/ - 50ppm. Hence I dose balanced Ca/Alk. However, since Ca/Alk isn't quite perfectly balanced consumption in my tank, I use ICP testing and make corrections every 6 months to a year.

How to balance Ca/Alk in the reef aquarium?

After reading: http://www.reefkeeping.com/issues/2004-12/rhf/ Here are my takeaways: For most practical purposes, Ca and Alk are consumed equally. However, "...the demand for calcium and alkalinity may not be precisely balanced at 20 ppm calcium per 1 meq/l of alkalinity..." The biggest...

www.reef2reef.com

My experience with most hobby grade test kits have led me to the same conclusion about their lack of accuracy.

I've also read in some posts that the Hanna Calcium Checker is either difficult or unreliable, so I haven't purchased it yet.

With the noticeable difference between the Hanna Alk checker and ICP testing, I'm scratching my head a bit. Running an ICP periodically will be helpful, But, while I expect small differences between ICP and hanna checkers, I fear the differences I've noted here exceed what should be considered "small".

 

[DivingTheWorld]

The issue with Alk for me is how to get confident in either number since they are so different. The Hanna Checker and reagents are only 2 months old, and I'm confident I followed the instructions correctly. On the other hand, customers of professional labs have to have a high degree of confidence in their tests also.

So, have other hobbyists had similar discrepancies and how did they resolve them seems to be a relevant question.
Try a third test kit for Alk, who knows what I'll see?

I find the Hanna Alk checker to be consistent. I trust it. I also run an Alkatronic so I cross reference the two.

 

[threebuoys]

I find the Hanna Alk checker to be consistent. I trust it. I also run an Alkatronic so I cross reference the two.

Have you ever compared ICP results to the Hanna Alk?

 

[DivingTheWorld]

Have you ever compared ICP results to the Hanna Alk?

Not in years, no. I did an ICP test years ago because I had a crash and wanted to know if there was something off in my water. As I recall it was at least close to my Hanna result. I've never really understood the reasoning behind regular ICP tests. I'm more concerned with consistency throughout the day, especially with Alk. Alkatronic allows me to track that.

 

[threebuoys]

Not in years, no. I did an ICP test years ago because I had a crash and wanted to know if there was something off in my water. As I recall it was at least close to my Hanna result. I've never really understood the reasoning behind regular ICP tests. I'm more concerned with consistency throughout the day, especially with Alk. Alkatronic allows me to track that.

I had not intended to use ICP testing, I agree that consistency is my objective, not necessarily during the day, but at least day to day, week to week.

However, I would at least like to know that my benchmark/starting point, is reasonably accurate The ICP suggests my calcium is too high, while the test kit I was using says I'm within a reasonable range. The Hanna Alk check is .57 higher than ICP. I suppose either number would work as a benchmark, but I was expecting perhaps .20 +/-

 

[Ober_Reef]

I have Hanna but use Salifert out of simplicity.

 

[gbroadbridge]

I just received my first ATI water test report for a 1 year old tank and discovered my calcium was at 520 which is considerably higer than the 440 I calculated using an API kit. I had added calcium chloride a week befor the water sample to raise the levels up from 360, not realizing the test kit was reading significantly below actual.

My alkalinity test using the Hanna Checker (HI772 checker) also gave me a much different reading than the ATI test. 7.83 for ATI and 8.40 for Hanna. Not sure what's going on here either.

So, before I continue with any tyoe pf dosing, I need to get control of my measuring devices.

Any suggestions?

For the most part, Consistency is much more important than the actual number.

If your test method gives repeatable results, just keep the reading stable.

With Hanna Alk reagents, I test using a new bottle, mark the variation from the old, and then use that new number as the one to maintain.

For Ca and Mg, well I hardly ever check them, because dosing 2 Part or Balling they'll be close enough.

 

[Randy Holmes-Farley]

My recommendation for alk is to do a titration yourself with a high quality commercial acid. As long as you have a decent pH meter, there's no colors involved.

A DIY Alkalinity Test: By Randy Holmes-Farley - REEFEDITION

Alkalinity is one of the most important measurements that a reef aquarist can make. It can become rapidly depleted in many aquaria, requiring frequent measurement in order to maintain stable levels.

www.reefedition.com

 

[gbroadbridge]

My recommendation for alk is to do a titration yourself with a high quality commercial acid. As long as you have a decent pH meter, there's no colors involved.

A DIY Alkalinity Test: By Randy Holmes-Farley - REEFEDITION

Alkalinity is one of the most important measurements that a reef aquarist can make. It can become rapidly depleted in many aquaria, requiring frequent measurement in order to maintain stable levels.

www.reefedition.com

Yes, Your method in that article was what I used to initially determine the offset to apply to the Hanna reading, which was suprisingly far off at 8dkH despite their test cuvettes reading spot on at 5dkH.