Hanna Calcium checker and distilled water

[blackstallion]

Did a search but couldn't find anyone trying this. I bought some Walmart vapor distilled water (with no minerals added back in for "taste") and ran a test on it to see if any trace calcium would be detected. However, since the low end of the Hanna Calcium checker is 200ppm, it came back with 200ppm. Can I assume then, for the purpose of using the Walmart distilled water in place of the Hanna deion solution, that my readings should be accurate and not skewed high?

 

[The Giz]

Yes, you can use distilled water - may be even more accurate than de-ionized -

 

[Randy Holmes-Farley Verified Community Expert]

That result is not useful, but I expect the water is fine.

What did you use as a blank for the distilled water? It would presumably be some other type of highly pure water. If you have that, then you have something to use even without the distilled water. lol

 

[blackstallion]

That result is not useful, but I expect the water is fine.

What did you use as a blank for the distilled water? It would presumably be some other type of highly pure water. If you have that, then you have something to use even without the distilled water. lol

I used the distilled water for both....ie. 9mL for when Hanna calls for their DI solution and then also for the 1uL of sample.

I'm assuming you believe this result is not useful because anything less than 200ppm would not register....and assuming if the Calcium level of the distilled water was even 10ppm, I would never know from this test.

 

[Randy Holmes-Farley Verified Community Expert]

I used the distilled water for both....ie. 9mL for when Hanna calls for their DI solution and then also for the 1uL of sample.

I'm assuming you believe this result is not useful because anything less than 200ppm would not register....and assuming if the Calcium level of the distilled water was even 10ppm, I would never know from this test.

Right.

 

[KenRexford]

Use the Walmart water to cut a known sample. If, say, your saltwater in the tank is 420, then cut that 50% tank water and 50% Walmart water. If the new result is 210, then Walmart was 0. If the new result is 310, then Walmart was 200. If new was something in between, then do the math.

 

[Randy Holmes-Farley Verified Community Expert]

Use the Walmart water to cut a known sample. If, say, your saltwater in the tank is 420, then cut that 50% tank water and 50% Walmart water. If the new result is 210, then Walmart was 0. If the new result is 310, then Walmart was 200. If new was something in between, then do the math.

The problem is that less than 1 ppm calcium is a big problem in the blank, and the Hanna won't be useful to detect that in any way.

IMO, it is a poor design. It uses only 0.1 mL of tank water, and that gets diluted up to 10 mL in the test. The requires a 100x multiplication in the value to get to the aquarium final value.

Thus, 0.1 ppm calcium in the blank (the zeroing sample) will also get multiplied by 100 to read as 10 ppm.

So 0.1 ppm calcium in the blank will make the aquarium value low by 10 ppm.

 

[Greg Hiller]

Randy, I actually like the test kit. I feel like I get pretty good numbers from it, but I hear your concern. Good lab technique is critical to not contaminate anything since tank water has so much calcium in it. Do you really feel like it's hard to get water for dilution with near zero calcium? Perhaps straight out of the RO/DI system with a new DI cartridge?

 

[Randy Holmes-Farley Verified Community Expert]

Randy, I actually like the test kit. I feel like I get pretty good numbers from it, but I hear your concern. Good lab technique is critical to not contaminate anything since tank water has so much calcium in it. Do you really feel like it's hard to get water for dilution with near zero calcium? Perhaps straight out of the RO/DI system with a new DI cartridge?

Hi Greg. I've never used it myself, and I don't know if folks are careful enough with their DI or not, but quite a few folks report differences between tests done with their RO/DI and when using distilled as the blank.

 

[Greg Hiller]

TDS meters are pretty cheap and probably accurate enough. I've used one in the past to get nearly 0 TDS on water coming straight out of the RO/DI.

 

[Randy Holmes-Farley Verified Community Expert]

This is a typical comment, although the result goes in the wrong direction for faulty RO/DI lol

Hanna calcium checker inconsistency

Hey, So I’ve been chasing 450 ppm calcium for the past few month. Been hovering around the 380 mark but just thought it was due to adding new corals all the time. My alkalinity is 9.0 also on a Hanna tester. On monday my calcium tested at 389. I added an adjustment dose of 25 ml (145 gallon...

www.reef2reef.com

"I get consistent, accurate (compared to my RedSea test) with the Hanna Calcium checker if I use store-bought distilled water and not RO/DI water. When I used RO/DI, my readings were too high."


I wonder how many of the complaints come from the pretty high uncertainty spec of the Hanna, and folks just assume the result should be better and if it is off, the RO/DI is to blame. lol


Hanna only claims +/- 25 ppm for calcium at 420 ppm.

 

[DWill]

I’ve had a pretty much brand new Ca checker sitting in my closet for almost a year. I’ll never use it again. I need to get rid of it, I just keep forgetting about it.