Alkalinity Test Kit Roundup

Discussion in 'Other Reef Talk' started by Eight, May 27, 2009.

  1. Eight

    Eight Guest

    I've been trying out a few different KH test kits and figured I would post some of my experiences with them. Unfortunately, because I don't have access to a significant amount of KH standard, I can't really comment on the accuracy of the tests... I will however, show photos of the test kit components and talk about the actual testing process as well as the clarity of the color change. (I'm typing up an overview of the instruction for each kit to illustrate testing complexity for actual instructions, please see packaging...)

    Here are the three KH test kits that I have. They are all pretty new kits, each purchased within the last two months, Salifert, Elos and API:


    ~$16 (100-200 tests depending on resolution)



    1) Add 5ml of tank water to test tube using syringe
    2) Add two drops of KH indicator to tube and swirl (I find the indicator bottle a pain. It's quite messy and stains everything.)
    3) Fill 1ml syringe with nozzle adapter attached with KH solution up to 1ml line
    4) Add drops of KH solution until test changes from blue/green to orange/red or pink
    5) Check number of ml's of KH reagent left in syringe and read corresponding dKH value in chart.

    The nice thing about the Salifert kit is that it now includes a little dKH standard of 7.3dKH (+- .3 dKH). This test is a little more involved than the other two because you need to add the indicator drops, fill the 1ml syringe precisely and also look up the corresponding dKH value in the table. The other two tests as you'll see are much simpler to execute. On the plus side, the salifert kit is more precise than the other two, presenting values in .3 or .4 increments. Also, since the syringe is graduated, you can infer a dKH value that is between two ml readings by splitting the difference.

    Next up, Elos:
    ~$18 (approx 60 tests)



    1) Add 5ml of tank water to test tube using syringe
    2) Drop KH reagent into the test tube one drop at a time, swirling after each drop. Count the drops and stop after you observe a color change from Cyan to Yellow. (I find this color change very subtle and hard to read.)
    3) Multiply the number of drops by 0.5 to find the dKH

    Elos recently changed their KH test kit from a 1 dKH precision to a 0.5 dKH precision kit. I actually really dislike this change because I can barely tell when the color changes from Cyan o Yellow. I used to be able to tell the change much more distinctly. That said, the quality of the test tube and syringe are really nice and the test is quick to perform provided you can detect the color change.

    Finally, API:
    ~$8 (Between 100 and 130 tests I think, they don't provide a number in their packaging...)



    1) Fill test tube with 5ml of tank water by dipping and then spilling out water up to the line on the tube. They don't include a syringe. (This tube is pretty crappy... it's really tall and thin and I find it difficult to get the water level to where I want without a syringe. I actually just use the Elos 5ml syringe to fill the Elos test vial and use that to test instead of the API vial.)
    2) Drop KH reagent into the test tube and shake between each drop. Count the drops and stop after you observe a color change from orange to green. This color change is extremely distinct, much more so than either Salifert or Elos.
    3) The number of drops is equal to the dKH of your sample.


    As I mentioned before, I can't comment on accuracy since I don't have enough dKH standard to compare with and I don't want to burn through the little 7.3 dKH included in the Salifert test kit. That said, I can rank the tests on the following criteria:

    Price (Cheapest to most expensive)
    1) API
    2) Salifert
    3) Elos

    Salifert might actually be cheaper if you use their low resolution mode and their 200 test estimation is accurate. API is cheap from an initial cost perspective. I picked my kit up in SF for only $8.99. Cheap is nice in that it doesn't discourage me from testing as often as I feel like.

    Quality of components (hardware, not reagents, since I have no way of measuring reagent quality)
    1) Elos
    2) Salifert
    3) API

    The Elos kit is really nice. The 5ml syringe has a rubber stopper and the test tube is glass. The Salifert kit is fine, but the components are cheaper, i.e.: no rubber gasket and plastic vial. That said, the Salifert components work just fine for their purpose... I hate the API test tube. It's so thin that you can't swirl it well. You're better off ditching that tube and using the hardware from either a Salifert or Elos kit.

    1) Salifert
    2) Elos
    3) API

    The Salifert kit is precise to 0.3 dKH, the Elos kit to 0.5 and the API to 1.0. The Salifert is probably even more precise since as I mentioned you can read between the MLs on the syringe.

    Ease of Use
    1) API
    2) Salifert
    3) Elos

    Once you get over the 'filling the vial' crapiness of the API kit, it's dead easy to use. The color change is by far the most distinct and the drops method is very easy to execute. There's no looking up value on a separate piece of paper, etc. On top of that the KH dropper is easy to open and drops cleanly and easily.

    Next, I like Salifert. I know there are more steps and there's even a table you need to look up, but the big reason why I think Salifert is easier than the Elos is because you can actually see the color change. Maybe I have a bad test kit, but I really have a hard time discerning the change on the Elos. It's to the point where i actually doubt my reading and redo the test to confirm.


    Overall, my daily test kit is an API. I know some people have questioned their accuracy, but what I did was just test the API kit against both the Salifert and Elos to ensure that it's at least inline with the other two. The Salifert I will use for times when I want a little more precision (i.e.: tuning a CA reactor) or when I have a little more time.

    I think this Elos KH kit will be the last one that I buy. I used to like them before they went down to .5 dkh, but now I can't recommend them because they're so hard to use.
  2. Mr. Ugly

    Mr. Ugly Past President

    What works best for me is to use the API reagents with the Salifert hardware.
  3. pixelpixi

    pixelpixi Guest

    Great writeup, Jason!

    API is my standard test kit too. I just really like the ease of use even if the drops may be a little less accurate.
  4. cwolfus

    cwolfus Past President

    Yup, nicely done!
  5. RavieReefer

    RavieReefer Guest

    That was really good! I will continue to use Salifert as I like the precision the kits give me :)
  6. sfsuphysics

    sfsuphysics Supporting Member

    Just by looking what you said, you can "make" an Elos kit by simply getting a 10mL tube with the API kit. I know this because I've done exactly this to "increase the resolution" to 0.5 dKH (not that I honestly care that much but for kicks and giggles I did it once). I do notice that the color is much less bright, and the change is more subtle. So the real question is... "are they the same regents and Elos is simply selling the same stuff at a higher cost?"
  7. Eight

    Eight Guest

    I think you're right Mike. You can probably get the .5dKH resolution by just using a 10ML test vial for the API kit. Similarly, you ought to be able to do the reverse with the Elos and use 2.5ML of tank water to save reagent and make it less precise.

    Glad people have found this useful... We talk about test kits all the time and I for one was always frustrated that there wasn't more information on them. For me, at least, ease of use is extremely important because if I don't like doing the test, it doesn't matter how accurate it is.. it'll just never get done.
  8. JAR

    JAR Supporting Member

    Nice comparison. Thank you for that.
    I have intuitively used the API as a quick check test and the Salifert as my accuracy test.
    I also use the API 5 in 1 test strips every once in a while to compare against other tests.
    The 5 in 1 gives me a hint if I have any nitrates also.
    I'll be able to sleep better knowing you have tested these kits.
  9. GreshamH

    GreshamH Guest

    OK wait, going into critical mode. The test kits are clearly marked with the price yet you posted a different price :lol:

    8.99 is not ~8 but for all but one penny if 9 bucks. 21.99 for a ll but a penny is 22, not ~16 :lol:

    The Salifert locally goes as far up as $26.

    Other then that, great write up. now find out what is each step is actually doing and what it is :)
  10. Eight

    Eight Guest

    I was using pricing off of Premium Aquatics and other online vendors... I did source these particular test kits locally, but since there is so much variability in pricing from LFS, I tried to use 'readily available, lowest pricing' from various online sources. I've found that online pricing tends to be more consistent compared to LFS pricing.
  11. GreshamH

    GreshamH Guest

    Bob hiss...promoting online store prices over that of TRUE BAR sponsors. Sure, post teh flipping WHOLESALE price of them and really get people in a hissy when they go to buy them locally. IMO posting online prices for a readily available local item flies int he face of BAR. Has Premium done ANYTHING to help BAR? Do they care about the industry other then a dollar? Does paying a vendor in another state help our tax base either on a state or local level? Can you find a bigger button to push of mine :)
  12. Eight

    Eight Guest

    Latest prices from various online vendors as of 5/28/09. You'll note that I used a tilde to indicate that I was noting "approximate pricing". Generally speaking, I think I was pretty accurate in terms of providing users with a general target price for what to expect from an online vendor. I was actually a bit off on API. It's even cheaper online than the ~$8 that I had previously posted.

    Marine Depot: $14.99
    Premium Aquatics: $15.39
    Aquacave: $15.95 $15

    Marine Depot: $17.99
    Premium Aquatics: $17.99 $19.79
    Aquacave: $17.99

    Marine Depot: $6.29 $$6.28
  13. sfsuphysics

    sfsuphysics Supporting Member

    Well in all fairness, I question how much local buying really helps our tax base... especially when one pays in cash.. . and I'll just leave that right there with no further explanation.
  14. A_Lee

    A_Lee Guest

    Meh, I don't think the whole pricing thing was a big deal really.
    That was a great comparison you did Jason -very helpful, thanks! :D
  15. Eight

    Eight Guest

    I was just trying to provide a helpful KH kit review for the benefit of BAR members, not push buttons, promote particular vendors, or anything like that. :)

    I do support local stores... in fact, that Salifert kit was purchased from Robert (Neptune), the API was purchased from Lucky Goldfish (SF, not sure if they're a sponsor, but I bought it from Anthony who was working there are the time. :p) I have in the past purchased my Elos kits from Aquatic Gallery, but yes, that particular one in the photo came from Premium Aquatics.

    Yes, we should support LFS and our sponsors when possible/feasible. At the end of the day, though, people are free to purchase their supplies from wherever they like. I felt it would be more helpful to indicate a relatively tight 'online range' for the test kit pricing rather than the quite wild price range from LFS.

    Also, FWIW, I have found Premium Aquatics have *exceptional* customer support. They've even taken care of me when I've encountered problems with other vendors' products!
  16. mray2660

    mray2660 Treasurer


    Excellent post. Do we have a head to comparison on accuracy between these kits? I found the difference between API and ELOS to be 3.5 units in my hands.

    Mke Ray
  17. Eight

    Eight Guest

    I think that the two missing bits of information needed to really properly do a KH test review are:

    1) Accuracy (How closely does the test kit reflect the actual chemical value being tested?)
    2) Consistency (How reproducible are the results?)

    Unfortunately, I can't test either of these... and they are probably the most important two things to test! :p I know Gresham might be making up some KH standard though. I think that's a great idea to make available to people.

    Mike, I have also found API to test a bit higher than my Elos. I think it's only about 1.0 to 1.5 higher or so though.
  18. mray2660

    mray2660 Treasurer


    I found it the other way for me. The API kit was 6, elos was 9.5. When I took water sample to Robert at Neptune he tested with Salifert he found it to be 9.6. Having a reference standard is excellent idea. That would be similar to a pH meter calibration solution. It would be nice to have that because I have problems on what is the true end points on all the test kits.

  19. tuberider

    tuberider Guest

  20. MontanaBay

    MontanaBay Guest

    When I saw the title of this thread it reminded me of articles in my other favorite website, Tom's Hardware, it would be cool to see other reviews of reefing products, maybe we can get BAR sponsors to front the products and the write-up will inform the group and send them out with better knowledge of what they are buying! Nice work!



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