Salifert vs Red Sea Pro

[downbeach]

I just re tested these two kits yesterday. The first test was done on 11/21/2011.

Salifert, Ca, Mg and Alk kits total: $61.20

# of tests/cost
Ca = 50 @ $ 23.40/kit $.48 ea./per test
Mg = 50 @ $ 24.30/kit $.49 ea./per test
Alk = 100 @ $13.50/kit $.14 ea./per test

Red Sea Reef Foundation Pro Kit: $49.99

# of tests/cost (using refill costs)
Ca = 75 @ $13.00/refill $.17 ea./per test
Mg = 100 @ $12.00/refill $.12 ea./per test
Alk = 75 @ $12.00/refill $.16 ea./per test

There is a real cost savings with the Red Sea kits. But, how did they test out as far as accuracy?

I've done three sets of tests now over the last three weeks.

Salifert

Week 1 Ca = 410 Week 2 Ca = 400 Week 3 Ca = 420 -------7/7/12 Ca = 410
Week 1 Mg =1350 Week 2 Mg = 1340 Week 3 Mg = 1340 -- 7/7/12 Mg = 1350
Week 1 Alk = 8.6 Week 2 Alk = 9.3 Week 3 Alk = 8.9 -------7/7/12 Alk = 8.6

Red Sea Pro

Week 1 Ca = 400 Week 2 Ca = 390 Week 3 Ca = 410 ------ 7/7/12 Ca = 400
Week 1 Mg =1360 Week 2 Mg =1350 Week 3 Mg = 1350 ---7/7/12 Mg = 1350
Week 1 Alk = 8.4 Week 2 Alk = 9.0 Week 3 Alk = 8.7 -------7/7/12 Alk = 8.5

I think the numbers speak for themselves. I will continue to monitor these tests until my Salifert kits are used up.

The one caveat here is that the Red Sea kit calculation is determined by taking your end point reading from the plunger in the syringe and deducting it from the 1mL you started with, to determine how much of the titrant was used, i.e. if the reading on the syringe is .37 you used .63, which is the number you need to determine your reading. It isn't hard, but you have to do the math, and I see it as an area for potential human error. The Salifert kit just gives you the reading without the user having to do any additional calculations.

[Jcurry@wesketch]

How do you know what the source water parameters are to begin with? Theoretically your water could be Ca 420 Mg 1400 & Alk 9.5 which would make the Red Sea kits very inaccurate compared to the Salifert.
Did you read this article http://www.advancedaquarist.com/2012/6/chemistry? I'm not sure what to make of it as all of the test kits seemed pretty inacccurate to me.

[downbeach]

The results are negligible, I could have gotten the same type of differences if I had compared two different Salifert or two different Red Sea kits against each other.
I have been using the Salifert kits for years, and have always checked the kit I had been using against a new one I was about to put in service, for comparable accuracy, and find these same differences.
These tests were done, using the same water, by the same person. So, any flaws in the testing procedures would be consistent. The test kits were both current (not expired, or have no expiration date).
What would you use to measure the "true" source water parameters? You would need some very sophisticated equipment that would break it down to the molecular level, and I don't think any of us here would have the time, inclination or funds for such a device.
This exercise was intended to test the accuracy vs cost of two over the counter test kits.
Salifert has been around for a while and is generally respected as being reasonably accurate, but is a little on the expensive side.
The new Red Sea Pro kits are relatively new, advertised as better than its predecessor, and considerably less expensive than the Salifert.
So, based on these tests, it's obvious that you can get the same results with less expensive test kits.

[redfishbluefish]

Having preformed a complex statistic analysis by scratching my head and cleaning the ear wax in my left ear with my pinky finger, I’ve determined that there is no difference in chemical results between the Salifert kit versus the Red Sea Pro kit. However, there is statistical difference in the cost of performing these tests. Red Sea Pro (refill kit) is statistically cheaper to perform.

In all seriousness, both test kits are titration tests, most likely using the same chemistry. There are inherent errors when performing this type of chemistry. However, these errors are well within the ballpark figures we need to know for good tank husbandry.

That said, what I really like about Red Sea Pro is that little extra ergonomic design that went into their kits. Again, the chemistry is the same, but the little design differences make the Red Sea kit that much easier to use. Because of Jim’s earlier post on this subject, I purchased the Red Sea Pro kit, and won’t look back…..I love it. Even if the costs were the same, I prefer the Red Sea because of ease of use. That’s my two cents!

[Jcurry@wesketch]

What would you use to measure the "true" source water parameters?

I don't know.

If you read the link to Advanced Aquarist article you can see that some of the test kits are fairly consistent in the tested values even though they are way off the "known" water parameters.

Too bad we don't have a chemist in our club who can do some experiments. hint hint