Ca Test Kits Results Compared? - Seachem vs. Salifert?

[Shallowwaters]

Anybody every compare results with Seachem and Salifert Ca test kits?
I found there may be a significant difference in test results.
I use Salifert for all of my other chemical tests, but when I test Ca with Seachem just after Salifert I get a different reading by over 10%. The first time it was 490 ppm Salifert vs. 430 with Seachem. Subsequently the difference was a bit smaller.

Since the Seachem Ca kit comes with a reference test, I performed a couple and each showed I was getting an accurate reading according to Seachem. So, since I only have one box of Salifert Ca test and it doesn't come with a reference test, I cannot validate the Salifert results.

Has anyone else found such a discrepency betwen these test kits?

If Seachem IS more accurate, then I have been undershooting my Ca level for many months.

 

[Moe_K]

Is there a margin of error listed on the tests?

And how many ppm does one drop of reagent equal?
I'm assuming you have to count drops or measure mililiters added, yes?

 

[NateHanson]

Is the seachem the one where you multiply the number of drops by 20? I didn't like that one because 20ppm is a pretty large window for my tastes.

 

[Kim]

Sallifert has recently made some changes to their CA tests. It changed the results to a higher number compared to other manufacturers and also to the older Salifert test kit.. Since Salifert changed their tests I haven't felt as comfortable with the results as I did before. Habib discusses the changes on RC in the Salifert forum and they make sense and he claims the test is more accurate than anything out there now for aquarium use but personally by changing the test it just left me not knowing what to believe.

http://reefcentral.com/forums/showthread.php?s=&threadid=437357

http://reefcentral.com/forums/showthread.php?s=&threadid=474610

 

[this is me]

I always use the salifert test ever since i started.
I think i went through 3 calcium test kits and I dont remember drawing 3ml of sample water, its always been 2ml. Since when did they change? The post started in september 04 but I've been using the test kit since march 04.
I also have another calcium test kit at home which I think its seachem but I'm not sure. Its a yellow box and you have to count the drop of the reagent3 and multiply by 20. I hated that kit. I tend to lose count after 15 or so. but i remember the result wasnt the same as the salifert's.
I'll verified this when i get home.
On the side note, that Pinpoint Calcium monitor is looking good. Real good....

 

[Jim Tansey]

I use both Salifert and Aquarium Pharmaceuticals and have been recording both values a couple of times a week for the last two months. I was intrested in the Aquarium Pharmaceuticals kit as I was told by a "Pro" that it's one of the best kits available, costs only $4-$5, does lots of tests, easy to see the color change, and accurate. I must say after using both the best I can say is my Calcium is someware between 450 and 480, and I seem to get more consistant results with the A.P. kit as the color changes quicker making it easy to read. As for absolute accuracy all I can say is they are close to eachother and for the price difference and ease of use I like the Aquarium Pharmaceuticals kit (No I don't own the Co.).

Jim

 

[wrassefan]

I use the red sea test kit and it is how many drops multiply by 50. It has been fairly accurate when I compared it with another kit (can't remember)...both had same results.

 

[ScottM]

i use the seachem. I trust a reference kit over one that does not come with one.

same for the mag test kit.

 

[clamm]

I also use and trust seachem. I compare the results with a cheap hagen test and find they are with in 20 of each other...so one will read 470 and the other 450, either way im fine.

I like the seachem test, I only wish I owned the company

 

[this is me]

I just came home and the test kit is not seachem. Its Sera.
I did the test and my calcium is at 400ppm assuming i did it correctly.
My salifert says 450ppm(like always)
At this point, I dont know which to trust but I always been using salifert and my tank is looking fine.

 

[NateHanson]

I use the red sea test kit and it is how many drops multiply by 50. It has been fairly accurate when I compared it with another kit (can't remember)...both had same results.

Multiplied by 50 Andy?? That means you can't get more accurate than "somewhere between 400 and 450"? Am I understanding correctly? That doesn't sound very useful.

 

[Liam]

What about LaMotte? has any one used their calcium test.

 

[Shallowwaters]

The Seachem kit I'm using is the Seachem Reef Status Calcium test. It uses 1 ml sample water and a little pink plastic cup full of RO/DI water. 1 drop of a reagent, plus 1 scoop of a purple powder - can't forget the powder! No multiplying - you just titrate and then look at a chart that has pretty low resolution. But even accomodating for the low resolution - increments of 20 ppm - it still is differs from my carefully administered Salifert test between 60 and 90 ppm.

Thanks for the tip on Aquarium Pharmaceuticals. I will probably give that a try along with LaMotte at some point. Clearly LaMotte would be the cold standard, but I probably would not use it as often because their kits have so many steps required to get a good result.

Scott's probably right about sticking with a kit with a reference test...

Thanks guys.

If somebody has one of the new American Marine Ca tests it would be cool to hear how it compares!

 

[MarkO]

REgarding the Seachem, does anyone know if they sell replacement titrant?
I'm starting to run low and of course I've still got > 90% of the other parts.

 

[Liam]

Mark O,i have a half full bottle of titrant you can have,i'll take it to the meeting if you're going.The humidity wrecked my purple powder and i"m going to try the LaMotte test next,Liam.

 

[ScottM]

i have seachem, salifert, lamotte and Hache.
seachem is my favorite.
I have the one in the plastic box.

 

[MarkO]

Mark O,i have a half full bottle of titrant you can have,i'll take it to the meeting if you're going.The humidity wrecked my purple powder and i"m going to try the LaMotte test next,Liam.

awesome!

 

[denvig]

I use the Seachem and feel it is accurate because if I do a test on the reference solution it gives the correct results of 400. The only thing you need to be careful about is measuring the powder. You want to pack it in the spoon and then scrape off the top to make it level. If it?s too loose or over filled your results will vary.

 

[NateHanson]

Has anyone used a salifert kit to test the reference solution?

 

[denvig]

Has anyone used a salifert kit to test the reference solution?

I would but I don't have a salifert Cal. test kit.