Test kits
- Thread starter tperk9784
- Start date
coralfragger101
Gone Postal
I'm going to bring this thread up one more time.
I believe that the only debatable point on test kits would be ease of use. If I created my own test kit that all you had to do was add one drop of regeant to 5 ml of water, swirl and then compare to a chart that every mark was a different color of the rainbow I believe I'd have a pretty easy to use test kit. But what good is it if it isn't accurate?
Maybe there has been controlled scientific studies to see which kits come closer to controlled lab results but I personally have not found or read any and I will assume that most folks probably haven't either.
This means that the general population is more than likely listening to advertisements and word of mouth of others as to what they think is a good test kit. Unless some one out there has the equipment needed to really do a test case, I doubt we will ever learn which kits are the most accurate.
I only bring this up again because of something that happened at the last meeting. Jeff used my Elos kit to test his water for PO4.
Below is an excerpt from the thread "Post your test numbers"
PO4: undetectable (salifert kit), .07 (Elos, thanks coralfragger)
It didn't dawn on me till after I left the meeting that these test results are substantially different. I qualify both Saliferts and Elos as above average yet if Jeff was using a Salifert's kit, he wouldn't worry about his PO4. Why should he - it's undetectable? On the other hand, if Jeff uses the Elos kit and comes up with .07 then it's time to take some action since we want that level at .03 or below.
Why such a big difference in test results from two quality kits?
I do not have the answer to that but I would be interested in doing more follow up on this. I wonder what would happen if we took a sample of water and simply picked three people out of the crowd and had them all individually test the water with both the salifert's and the elos kit and then compare results.
Would we find that one kit doesn't measure the same on the same sample water?
Would we find that the difference in test readings between the two kits is actually closer than what Jeff came up with on his initial testing?
Would we begin to see that there may be other variables that enter into the picture? People don't follow directions the same or read a syringe the same?
If there is any interest in doing this, I will bring the Elos PO4 kit to the next meeting and we'll see what happens.
I believe that the only debatable point on test kits would be ease of use. If I created my own test kit that all you had to do was add one drop of regeant to 5 ml of water, swirl and then compare to a chart that every mark was a different color of the rainbow I believe I'd have a pretty easy to use test kit. But what good is it if it isn't accurate?
Maybe there has been controlled scientific studies to see which kits come closer to controlled lab results but I personally have not found or read any and I will assume that most folks probably haven't either.
This means that the general population is more than likely listening to advertisements and word of mouth of others as to what they think is a good test kit. Unless some one out there has the equipment needed to really do a test case, I doubt we will ever learn which kits are the most accurate.
I only bring this up again because of something that happened at the last meeting. Jeff used my Elos kit to test his water for PO4.
Below is an excerpt from the thread "Post your test numbers"
PO4: undetectable (salifert kit), .07 (Elos, thanks coralfragger)
It didn't dawn on me till after I left the meeting that these test results are substantially different. I qualify both Saliferts and Elos as above average yet if Jeff was using a Salifert's kit, he wouldn't worry about his PO4. Why should he - it's undetectable? On the other hand, if Jeff uses the Elos kit and comes up with .07 then it's time to take some action since we want that level at .03 or below.
Why such a big difference in test results from two quality kits?
I do not have the answer to that but I would be interested in doing more follow up on this. I wonder what would happen if we took a sample of water and simply picked three people out of the crowd and had them all individually test the water with both the salifert's and the elos kit and then compare results.
Would we find that one kit doesn't measure the same on the same sample water?
Would we find that the difference in test readings between the two kits is actually closer than what Jeff came up with on his initial testing?
Would we begin to see that there may be other variables that enter into the picture? People don't follow directions the same or read a syringe the same?
If there is any interest in doing this, I will bring the Elos PO4 kit to the next meeting and we'll see what happens.
Rogger Castells
New member
I think you are jumping into conclusions ahead of time, you are assuming that the elos kit is correct and the Salifert is wrong only because the elos test kit showed that the water had Phosphates, what if the Elos kit is wrong and the salifert was right? then you will be worry for no reason ! 
or what if one of the test was performed wrong, I think to be absolutely sure of anything the water will need to be tested again or perhaps with a LaMotte kit
or what if one of the test was performed wrong, I think to be absolutely sure of anything the water will need to be tested again or perhaps with a LaMotte kit
coralfragger101
Gone Postal
Rogger: I wasn't jumping to conclusions at all. I did not ever say that the Elos kit was correct. In fact, I stated that without a controlled test we would never know which is more accurate.
I merely brought up the difference in the two and think it is interesting enough for further investigation.
I merely brought up the difference in the two and think it is interesting enough for further investigation.
jeffbrig
Premium Member
I've run acros stories of a couple of people mixing solutions with known concentrations and doing test. For example, here's a post by Greg Hiller testing a Hanna PO4 kit against water spiked with known quantities of PO4. All it takes is someone who has the knowledge, access to a chemistry lab stocked with the right chemicals.
http://www.reefcentral.com/forums/showthread.php?s=&postid=9984285#post9984285
I don't know if anyone has done the same with Salifert or Elos PO4 kits the same way. I have read posts from RHF (RC's resident chemistry guru) and others that have confirmed the accuracy of the more common Salifert kits (calcium, alk, etc.) as being quite high. But, PO4 is apparently a case where it's difficult to engineer a test kit that can accurately read low range PO4 while being easy to use and inexpensive. That's pretty obvious when you look at the $100 tests that are typically recommended by the sps crowd.
Personally, I've never felt terribly comfortable with the results of the Salifert PO4 kit, since I and so many other people always read 0 with it. I don't think anyone who has posted in the "test results" thread showed any detectable phosphate. Maybe it's a problem with a quickly aging test reagent. Maybe it's a problem with reading the color of such a thin layer of water.
I think ReefWreak has the right idea, btw.
