Rybren
Valuable Member
I know that there have been a few threads about this, but I wanted to share my experience.
I used to only use the API test kit, but switched to Salifert last year when I set up my latest tank.
I find the color card difficult to read, so now I get the opinions of my sons when doing a test. According to the Salifert test, Nitrates were always showing between 25 and 50. Although the tank never looked like the nitrates were that high - good coral growth, no algae in the DT, slow growing macros in the sump and slow growing algae on the ATS, I started to dose the DIY NOPOX.
Nitrates came down, but never lower than 25. This didn't make any sense to me, but then I came across the threads discussing issues with the Salifert color cards. My card is the one with the black lines. When I looked at some of the side by side images of the old cards and this new one, there certainly were some huge differences. I reached out to Habib to get a new card, but he has never responded to me.
I got a color app for my phone and found an old color card at the LFS, then I did a color comparison of the two cards. The app isn't perfect but here's what it showed:
First Number is the reading using the new card and the second is using the old card:
2 - 1.5
5 - 3.5
10 - 4
25 - 5
50 - 9/10
100 - 100
I then did a test of my tank water and compared the results using both cards. On the new card, the result was a bit pinker than 25. On the old card, the result was about 5. This matches the results that the app gave me pretty closely. It also more closely resembles what I see and would expect from my tank at this nitrate level.
A couple of days ago, I bought a Seachem Nitrate test kit just because it came with a reference sample.
Using the reference sample, which is supposed to be 10 mg/L, the Seachem test kit read a tad over 10 mg/L. Using the Salifert test kit, the reference sample read 50 ppm. I know that there is a difference between mg/L and ppm, but it is very small and wouldn't explain the difference in the test results. I had returned the old Salifert test card to the LFS, so I couldn't use it for this test, but it does match the results that I found above.
I then tested my tank water using both tests. The Seachem test showed 5 mg/L and the Salifert test showed a bit more than 25 ppm. Again, this result matches what I saw with the difference in test cards.
I just thought I'd share with the group.
I used to only use the API test kit, but switched to Salifert last year when I set up my latest tank.
I find the color card difficult to read, so now I get the opinions of my sons when doing a test. According to the Salifert test, Nitrates were always showing between 25 and 50. Although the tank never looked like the nitrates were that high - good coral growth, no algae in the DT, slow growing macros in the sump and slow growing algae on the ATS, I started to dose the DIY NOPOX.
Nitrates came down, but never lower than 25. This didn't make any sense to me, but then I came across the threads discussing issues with the Salifert color cards. My card is the one with the black lines. When I looked at some of the side by side images of the old cards and this new one, there certainly were some huge differences. I reached out to Habib to get a new card, but he has never responded to me.
I got a color app for my phone and found an old color card at the LFS, then I did a color comparison of the two cards. The app isn't perfect but here's what it showed:
First Number is the reading using the new card and the second is using the old card:
2 - 1.5
5 - 3.5
10 - 4
25 - 5
50 - 9/10
100 - 100
I then did a test of my tank water and compared the results using both cards. On the new card, the result was a bit pinker than 25. On the old card, the result was about 5. This matches the results that the app gave me pretty closely. It also more closely resembles what I see and would expect from my tank at this nitrate level.
A couple of days ago, I bought a Seachem Nitrate test kit just because it came with a reference sample.
Using the reference sample, which is supposed to be 10 mg/L, the Seachem test kit read a tad over 10 mg/L. Using the Salifert test kit, the reference sample read 50 ppm. I know that there is a difference between mg/L and ppm, but it is very small and wouldn't explain the difference in the test results. I had returned the old Salifert test card to the LFS, so I couldn't use it for this test, but it does match the results that I found above.
I then tested my tank water using both tests. The Seachem test showed 5 mg/L and the Salifert test showed a bit more than 25 ppm. Again, this result matches what I saw with the difference in test cards.
I just thought I'd share with the group.
