Salifert Calcium Test Help

[SCUBAFREAK]

I just purchased a Salifert calcium test yesterday and went home to test my calcium. i followed the directions closely and it says to add reagent ca-3 one drop at a time till the mixture turns from pink to clear blue. the first time i did it i put all the ca-3 reagent in and it didnt turn at all. so the next time i tried the lower resolution and it turned blue at 0.24 then it says to multiply the calcium values by 2. 0.24 gives me a calcium conentration of 380. my question is do i multiply the 380 by two or the .24 by two. if i multiply the 380 by two my calcium is 760. if i multiply the 0.24 by two then my calcium is 260. either way it isnt good. anybody have experience with this test kit. i would appreciate it

thanks
Ryan

[Bebo77]

yes low test is x2 your Ca is 760 that is why it did not change the 1st time you did it...

[Randy Holmes-Farley]

You can just use a second syringe of titrant in the original method and add the values together.
This thread discusses high calcium, as does the article below:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=934649

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

[SCUBAFREAK]

so my calcium is way high. How bad is this? any suggestions on bringing it down. What would be my next step?

thanks
Ryan

[Randy Holmes-Farley]

The thread and article above discuss it. :)

[salt-lik]

That's interesting. I tried the Salifert kit also and get the same type of problem....calcium is way to high :eek:.

However, I then tried the SeaChem and its much more reasonable (380 ppm) :).

I then tried the SeaChem with the reference sample provided in the kit and it read as it should (400 ppm) :)

I then tested the SeaChem reference sample with the Salifert kit and it tested way too high (can't remember the actual value) :confused:.

I've noticed that the SeaChem kit requires a dilution of the sample whereas the Salifert does not....I like Salifert for many of their kits but I'll stick with SeaChem for Calcium. The reference sample is a great idea, especially in instances like this one.

[Randy Holmes-Farley]

Well, it may certainly be true that your Salifert kit is off, but it is also possible that the Seachem kit is off. Maybe both are off. You don't have any independent way to know if that standard is correct, I presume. I agree that a reference sample is a good way to evaluate if a kit is performing the same way every time, but not necessarily to know what is accurate in seawater (which the standard will not be).

You might post a question in the Salifert forum here at RC. Habib can check to see if your kit might be too old, for example.

[Billybeau1]

Salt, I recently tried what you did and the reference sample of the Seachem was off.

Boy you just never know. Have your LFS or a friend test and see which one is closer.

We all want to believe that all test kits are supposed to be true, but, unfortunately there are too many variables for this to be an exact science.

[SCUBAFREAK]

Thanks everybody. i think i might get another test kit and see what happens. anybody have any experience with the red sea brand? that is the only other brand my lfs carries.

[Randy Holmes-Farley]

I've not used the Red Sea calcium kit, but a number of folks do not care for it, IIRC.

[Billybeau1]

Scuba, Do me a favor. Lets make sure you are testing correctly first.

2 ml water in the test vial

1 level spoon of Ca-1 (dont mix yet)

Add 8 drops Ca-2 - swirl (do not shake) for 10 seconds

Draw CA-3 reagent into sryinge until the black o-ring is at the 1 ml mark. (dont worry about where the actual liquid level is) just make sure the black o-ring is at 1 ml.

Start exhausting the sryinge into the test vial (I usually dump the first .50 ml in one shot) saves time.

Now start dripping 2 or 3 drops at a time swirling the vial for 5-10 seconds each time.

When you see your pink turning to purple, slow down a little.

2 drops swirl, 2 drops swirl, 2 drops swirl, until the solution turns from purple to pure blue.

Turn the sryinge upside down and take your reading at the top of the black o-ring.

Now, if you have exhausted the whole sryinge and the color did not change to pure blue, dont panic.

Fill the sryinge up again so the black o-ring is at the 1 ml mark and start again.

2 drops swirl, 2 drops swirl.

When the solution turns pure blue, you are done. Add the first value (500ppm) to the second value and you have your total calcium level.

Try this and let us know how it goes.

[Spuds725]

besides testing properly which Billy covered nicely (that air in the syringe messed me up the first time too)....

Just out of curiosity-- what is your Alkalinity and do you have any reason to believe that your calcium should be this high----- its hard to get calcium that high without adding a calcium supplement blindly-- I've never heard of a salt mix being that high.

[salt-lik]

Hey Billy,
Having other sources check your Ca++ levels is indeed a good idea. I did have my LFS check it thinking that maybe my SeaChem was expired and therefore incorrect. As it turned out, the SeaChem was still o.k and my values as I had assessed were valid. Anyway, I like your detailed description of how to use the Salifert kit. I'll try it again out of pure curiosity. I just found it wierd that the Salifert and SeaChem gave such contrasting results. I'm glad it wasn't just me!!
cheers.

[Billybeau1]

:thumbsup: Let us know how it goes. If your calcium is undeed 380 ppm, your vial should turn pure blue at around the .24 ml mark on the sryinge.

[Randy Holmes-Farley]

I just found it wierd that the Salifert and SeaChem gave such contrasting results.

It is not unusual for kits to disagree, even quite a bit. IMO aquarists have unwarranted expectations of accuracy with inexpensive kits. Also, there have been specific threads commenting on the Salifert vs Seachem calcium results. Here's a long one:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=640223

[SCUBAFREAK]

Thanks again guys. I will retest again tonight and let you know what i find. i actually find billybeau1's instructions easier to follow than salifert's. I think i may have bee reading it from the top of the liqiud line rather than the black plunger on the syringe. like i said i will retest using billy,s instructions and let you know what i get.

thanks again
Ryan

[SCUBAFREAK]

Ok i retested tonight and came up with a 490 reading. that sounds better. i figured out what i was doing wrong. a couple of things. I was reading the syringe wrong and i dont think i had all the ca1 dissolved before i added ca3. Thanks to all that offered advice i really appreciate it

thanks
Ryan

[Randy Holmes-Farley]

:thumbsup:

That sounds good.

Happy Reefing. :)