Salifert or Red Sea test kits?

[MyNameIs]

Hi everybody, so bascially I have been using Salifert to test my Calcium, Alk, and Magnesium. I just purchased the red sea kit to give it a try and I have run into something that has me boggled. The Salifert says that my calcium is 450ppm, when I use the red sea it tells me its low around 200ppm. This could completely be human error but i followed the instructions pretty sure I am doing the test correctly. My question is which do I believe? I tried searching the forum seems quite a few people on here use the red sea kits and say they are pretty good. Any input would be appreciated. My clam and my SPS corals seem to have good growth.

 

[AZDesertRat]

Salifert and Elos are top of the line.
The kits are not expired are they? They have a date on them.

 

[MyNameIs]

Kits are still good. I'm thinking I should go with what the Salifert kit says then.

 

[AZDesertRat]

Do a split sample, use your two kits and take part of the sample to your LFS or a reef friends also for comparison. That way you are using the same sample for all the tests and at least a couple should agree or be close.

 

[MyNameIs]

Thanks for the tip. Greatly appreciated.