Salifert testing higher dKh than Hanna

Discussion in 'Reef Aquarium Discussion' started by WhiskeyCoffee, Feb 13, 2018.

  1. WhiskeyCoffee

    WhiskeyCoffee Well-Known Member Build Thread Contributor

    Joined:
    May 28, 2016
    Messages:
    524
    Likes Received:
    387
    Location:
    Silverdale, WA
    So the other day I got some erroneous readings on my Salifert alkalinity test. First one was 9.6 dKh then two days later it was 12. I also tested a fresh batch of Reef Crystals and it came out 12 dKh. I panicked but everything looked healthy in my tank. Maybe I just screwed up the tests. I asked a buddy if I could borrow his Hanna and he said no prob. This is where it gets interesting. With the Hanna, I got:

    Tank: 8.4 dKh
    Reef Crystals: 11.0 dkH

    So I decided to do another test with the Salifert tonight. Being as precise as possible, I got:

    Tank: 9.5 dKh
    RC: 12.0 dKh

    Is this normal? I have about 3/4 of the Salifert test solution left so I'd hate to find out it's off. I know both tests are subject to human error but I've repeated the tests and got similar numbers all around.

    [​IMG]
     
    Cory likes this.

  2. Cory

    Cory Valuable Member R2R Supporter Article Contributor

    Joined:
    Oct 30, 2014
    Messages:
    3,822
    Likes Received:
    1,288
    Location:
    Grande Praire Ab, Canada
    Hello, get soem baking soda (sodium bicarbonate) at the grocery store. Go to the pharmacist and ask him or her to weigh out 1.135 grams of baking soda. Get 1 gallon of distilled water or ro/di. Put the soda in the water shake it up. Test your kit with this. It should be close to 10dkh. If not its off.

    May not work with hanna as its not titration based. But try them both anyway.

    Now you wont be confused.
     
  3. WhiskeyCoffee

    WhiskeyCoffee Well-Known Member Build Thread Contributor

    Joined:
    May 28, 2016
    Messages:
    524
    Likes Received:
    387
    Location:
    Silverdale, WA
    Hm... That's .227 of a teaspoon. Could I just do 1/4 of a teaspoon? How do you figure out x grams of baking soda = x dKh?
     
  4. Cory

    Cory Valuable Member R2R Supporter Article Contributor

    Joined:
    Oct 30, 2014
    Messages:
    3,822
    Likes Received:
    1,288
    Location:
    Grande Praire Ab, Canada
    No you cant. Youll still be confused because it can be off a lot. The baking soda needs to be precise, the water not so much. Its a recipe going around by chemists for a long time now. Like mpre than 20 years iirc.
     
  5. WhiskeyCoffee

    WhiskeyCoffee Well-Known Member Build Thread Contributor

    Joined:
    May 28, 2016
    Messages:
    524
    Likes Received:
    387
    Location:
    Silverdale, WA
    dang, alright. I just feel weird going in to the pharmacy with a white powder and asking them to weigh it... lol...
     
    Cory likes this.
  6. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

    Joined:
    Jun 6, 2017
    Messages:
    1,823
    Likes Received:
    3,322
    Location:
    Baltimore, MD
    I'm not sure I understand. What is your concern? Is it that the newly mixed saltwater is much higher than the tank? Or that the Salifert kit produces different results than the Hanna Checker?
     
  7. WhiskeyCoffee

    WhiskeyCoffee Well-Known Member Build Thread Contributor

    Joined:
    May 28, 2016
    Messages:
    524
    Likes Received:
    387
    Location:
    Silverdale, WA
    That's what I'm concerned with.
     
  8. chipmunkofdoom2

    chipmunkofdoom2 Always Making Something R2R Supporter Reef Squad R2R Excellence Award Article Contributor

    Joined:
    Jun 6, 2017
    Messages:
    1,823
    Likes Received:
    3,322
    Location:
    Baltimore, MD
    Personally, this would not bother me. These test kits are not always 100% accurate. While it would be nice if they all agreed, it's not unheard of to have two different results from two different testing methodologies. If the Salifert test kit produced consistent results, I would be satisfied.
     
    Gareth elliott likes this.
  9. WhiskeyCoffee

    WhiskeyCoffee Well-Known Member Build Thread Contributor

    Joined:
    May 28, 2016
    Messages:
    524
    Likes Received:
    387
    Location:
    Silverdale, WA
    That's kind of what I was thinking... All of these tests are prone to human error so I most likely will never know my tank's "real" dKh...
     
    chipmunkofdoom2 likes this.
  10. Gareth elliott

    Gareth elliott Read, Tinker, Fail, Learn R2R Supporter R2R Excellence Award Build Thread Contributor NJRC Member

    Joined:
    May 7, 2017
    Messages:
    2,335
    Likes Received:
    2,269
    Location:
    NJ
    Also agree The precision of tests is more important than accuracy. Loads of successful reefs anywhere between 7-11 dkh that have stability.
    I personally would be more worried if my reef salt differed that greatly from my tank with the same test kit, but that is me. Fwiw i think all the tests have a margin of error of 3-5%.
     
  11. Cory

    Cory Valuable Member R2R Supporter Article Contributor

    Joined:
    Oct 30, 2014
    Messages:
    3,822
    Likes Received:
    1,288
    Location:
    Grande Praire Ab, Canada
    Lol i had the same concern. Just bring an unopened box from the store ask. They were happy to do it for me. :) just tell them its for the fish tank.
     
  12. Cory

    Cory Valuable Member R2R Supporter Article Contributor

    Joined:
    Oct 30, 2014
    Messages:
    3,822
    Likes Received:
    1,288
    Location:
    Grande Praire Ab, Canada
    Fwiw 15 years ago salifert was off by like 4 dkh iiirc. I made a big stink. They then supplied alk standards in the box but dont now.
     
  13. Cory

    Cory Valuable Member R2R Supporter Article Contributor

    Joined:
    Oct 30, 2014
    Messages:
    3,822
    Likes Received:
    1,288
    Location:
    Grande Praire Ab, Canada
  14. Bmezz

    Bmezz Active Member

    Joined:
    Aug 30, 2017
    Messages:
    158
    Likes Received:
    46
    Location:
    OC California
    i rely on hanna for alk. salifert for calcium as hanna really tough for me to get accurate. hanna for phos ULR. salfert for mag, strot, amonia, ph.... I think they all have their tolerances but once i use one i stay with it and know if there is difference from test to test not test method to test method...
     
    tuanc704 likes this.
  15. Peanut

    Peanut Well-Known Member R2R Supporter

    Joined:
    Nov 26, 2012
    Messages:
    952
    Likes Received:
    294
    Location:
    Miami Beach, Florida
    I use a hanna checker and what I have found is that you have to be very careful when measuring reagents, water, sample to be tested, etc. If you do, I find it to be very consistent.

    At first, just like you I doubted the device itself because my readings were all over the place. I basically gave up on it and tried many others. At last year's Reef-a-palooza in Orlando, Hanna had a booth and I spoke to a rep and explained what I was going through (with both Alk and Ca). He suggested to me that if I really thought it was the device I should buy the calibration/reference set for the specific device and if it is the device that will surely tell me, and if it was the device I could call customer service etc. what?!?!? there's a reference set? So I bought them both (Alk and Ca), I believe they were less than $10 and worth a billion in piece of mind. I can tell you the checker reads the reference sets consistently every single time without any doubt.

    Hanna chimes in here https://www.reef2reef.com/threads/no-alk-reagent.353524/page-2#post-4454465

    Make sure you are accurate with everything you do.

    Having said all that, I'm going to run a test of the 1.135 grams of baking soda lol
     
Draft saved Draft deleted

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice
Loading...