Bad Test Kit?

[AtlantiCat]

I bought all of my test kits new in November and my Salifert test kit for Magnesium has consistently tested low from the first day I started using it (~1,020-1,160).

At first, I thought the issue might be that I hadn't shaken up the bag of salt (Reef Crystals) and the minerals were unevenly distributed. But it kept happening every time I mixed up a new batch. Exp is June 2025.

I picked up a Red Sea test kit and this one has been indicating the Magnesium is properly in range (~1,300).

I can't find this listed as a known issue for Salifert anywhere despite copious googling. Could it be that I just got the 1 in 1,000,000 faulty kit?

There are only Zoanthids and Sexy Shrimp in the tank.

 

[Fish Think Pink]

I bought all of my test kits new in November and my Salifert test kit for Magnesium has consistently tested low from the first day I started using it (~1,020-1,160).

At first, I thought the issue might be that I hadn't shaken up the bag of salt (Reef Crystals) and the minerals were unevenly distributed. But it kept happening every time I mixed up a new batch. Exp is June 2025.

I picked up a Red Sea test kit and this one has been indicating the Magnesium is properly in range (~1,300).

I can't find this listed as a known issue for Salifert anywhere despite copious googling. Could it be that I just got the 1 in 1,000,000 faulty kit?

There are only Zoanthids and Sexy Shrimp in the tank.

2nd opinions are always good to double check numbers. I've taken samples over to LFS for another opinion - depending test (and LFS) they might charge for doing water check(s) of parameter(s)

At least you know you weren't crazy!

Happy New Years!

 

[AtlantiCat]

2nd opinions are always good to double check numbers. I've taken samples over to LFS for another opinion - depending test (and LFS) they might charge for doing water check(s) of parameter(s)

At least you know you weren't crazy!

Happy New Years!

Yeah, maybe I'll do that. Not sure if my local charges or not, but worth a shot. Thanks and Happy New Year!

 

[Necrodaemus]

I bought all of my test kits new in November and my Salifert test kit for Magnesium has consistently tested low from the first day I started using it (~1,020-1,160).

At first, I thought the issue might be that I hadn't shaken up the bag of salt (Reef Crystals) and the minerals were unevenly distributed. But it kept happening every time I mixed up a new batch. Exp is June 2025.

I picked up a Red Sea test kit and this one has been indicating the Magnesium is properly in range (~1,300).

I can't find this listed as a known issue for Salifert anywhere despite copious googling. Could it be that I just got the 1 in 1,000,000 faulty kit?

There are only Zoanthids and Sexy Shrimp in the tank.

I’m not alone!!!! I have recently been struggling with the exact same issue using the Salifert Magnesium test kit. It was consistently giving lower numbers than what was expected…sometimes to the point that it appeared Mg was rapidly depleting. I started dosing Mg by 10ppm daily for a couple weeks and the test was still showing 1170-1200 when it should have been 1380-1400. I decided enough was enough and picked up the basic (non-pro) Red Sea Mg kit from LFS and tested my tank…1500ppm!! I mixed up 2 gallons of my salt mix to 35ppt and tested that with both kits…expecting around 1350 (I’m one of the rare ones that uses 50/50 Red Sea Coral Pro and blue bucket)…Salifert tested at 1230, Red Sea showed 1400.
It was suggested that there was potential that my salinity was off but I used 2 refractometers and a buddie’s Hanna salinity checker with 3 different calibration solutions and they all 3 showed my water at 35-35.5ppt.

 

[AtlantiCat]

I’m not alone!!!! I have recently been struggling with the exact same issue using the Salifert Magnesium test kit. It was consistently giving lower numbers than what was expected…sometimes to the point that it appeared Mg was rapidly depleting. I started dosing Mg by 10ppm daily for a couple weeks and the test was still showing 1170-1200 when it should have been 1380-1400. I decided enough was enough and picked up the basic (non-pro) Red Sea Mg kit from LFS and tested my tank…1500ppm!! I mixed up 2 gallons of my salt mix to 35ppt and tested that with both kits…expecting around 1350 (I’m one of the rare ones that uses 50/50 Red Sea Coral Pro and blue bucket)…Salifert tested at 1230, Red Sea showed 1400.
It was suggested that there was potential that my salinity was off but I used 2 refractometers and a buddie’s Hanna salinity checker with 3 different calibration solutions and they all 3 showed my water at 35-35.5ppt.

Out of curiosity...I can't find a manufacturer's date on the box, but mine expires June 2025. Does yours have the same expiry?

 

[bushdoc]

I have been testing my water regularly for over 10 year now with various brands. Once I had expired set, but all other times when my results were suspicious, I found out later it was an "operator error".

 

[AtlantiCat]

I have been testing my water regularly for over 10 year now with various brands. Once I had expired set, but all other times when my results were suspicious, I found out later it was an "operator error".

Well, when Salifert has multiple test kits that are run in a nearly identical manner (add water to vial, add colorant to water, add reagent to mixture until color changes) and everything in all the other similar kits comes up roses, it's kind of difficult to call it user error for just the one kit. If they all seemed to provide problematic results, I would be inclined to agree with you. But I even watched a few videos to make sure I wasn't doing something wrong and I'm running the tests as they're supposed to be run.

Also, this is Reef Crystals and RO water with no additives. It doesn't get much simpler.

 

[Necrodaemus]

Out of curiosity...I can't find a manufacturer's date on the box, but mine expires June 2025. Does yours have the same expiry?

I threw the box away before even checking but most of the other kits that I ordered from Amazon at the same time has an expiration date of 2024.

 

[Necrodaemus]

I have been testing my water regularly for over 10 year now with various brands. Once I had expired set, but all other times when my results were suspicious, I found out later it was an "operator error".

It’s not been user error in my case. I followed everything to the T. I also use Salifert for Calcium and Alk, those come out spot on with expected results.