Refractometer Calibration Fluid - Aquacraft - Uh Oh...

Discussion in 'Saltwater Tank Equipment' started by Nart, Aug 4, 2017.

  1. Nart

    NartWell Known MemberMember

    Refractometer Calibration Fluid..... I preach about it and use it. However, today I found a huge flaw.
    Which one am I speaking of in particular? The one below by Aquacraft.

    So, I use this calibration fluid on my Refractometer religiously to calibrate before I take any sample tests of the saltwater mix I make. I keep my tank at specific gravity of 1.026. Thus, the fresh saltwater batches I make before my water changes are also dialed in at specific gravity of 1.026.

    Well, recently I made a switch over to Fritz RPM salt from Red Coral Sea Pro salt. The reason is because I wanted a lower dKH (Alkalinity) value since I am starting to step into the realm of SPS coral keeping. Currently my dKH in my tank is about 11.5, which in a low nutrient tank will wreck havoc on SPS corals, but that's a story for another time.

    Anyways, I mix the Fritz salt at 1.025 because according to Fritz's parameter guide, mixing at 1.026/35ppt will achieve a dKH of 8-9PPM, which is what I want. I want to lower my dKH. I then run some tests.... and I'm getting dKH of 11PPM so I run a calcium and magnesium test on the freshly made batch, and calcium and magnesium was far beyond what my Salifert tests could test for Calcium was 500+PPM and Magnesium was 1500+ This wasn't right at all, so I added in some RODI water to lower the value till the Refractometer read 1.024... still and calcium and magnesium was unreadable. I tripled checked my Refractometer and tripled checked all my parameter tests, all the same.... hmmm....

    I decided to contact Fritz and told them the issue I was having, they sent me out a replacement box of salt and I quickly made a fresh batch @ just a little under 1.025, dKH was now 10, calcium was detectable but at 500PPM and Magnesium was around 1440... still high with the numbers. So I decided to take the fresh batch of newly made saltwater to my LFS and I asked them to test my salinity and calcium.... The owner comes over and said "I have good news and bad news for you"... I'm like uh oh... turns out my Salinity was 1.027 and calcium was 500+.... this would explain it but I am still boggled, my Refractometer could not be off especially if I calibrated with Refractometer calibration fluid before and after my water sample test to ensure the Refractometer was reading a correct specific gravity. I have had bad refractometers before and I can easily tell that it was a bad Refractometer because every time I tested the water or used the calibration fluid, my results were different each and every time. I asked my LFS if they were sure, they said they doubled checked with their digital salinity scale and with their store analog Refractometer.

    I go home..... and I run more tests and was talking to a local reefer and he said your Refractometer or calibration could be off. I told him no... my Refractometer is not off, I would know and how could calibration fluid be off? especially if it states it right on the bottle to calibrate it at 35ppt. Then it dawned on me.... I quickly grab my RODI water and I know it is pure as it can be. I used my Refractometer to test my RODI and it was reading in the -2 range.... it was well below the 0 line on the Refractometer.

    What?!?!?!?!??! So I calibrated my Refractometer with the RODI water to 0 and retested the calibration fluid. Everything made sense now. The results for the calibration fluid came back at 1.028, so I go to dig further and found that some reefers also tested Aquacraft's calibration fluid and found that their stated 35 PPT / 1.026 came back with results of 1.0286 specific gravity.

    OMG.... right? This whole time my tank has been just surviving at a higher salinity value. So after calibrating my Refractometer with RODI water for 5 times just to be sure it was holding a true 0 value I went to test my tank.... it was sitting at a specific gravity level of just under 1.029 holy ice cream fudgesicles.

    This proves a few things... corals and fishes are definitely hardy living creatures. I feel really bad, because I always thought I double and triple check everything... The thing that never crossed my mind was this Aquacraft Refractometer Calibration Fluid. I didn't doubt it because it had great reviews on Amazon, till I saw the more recent reviews from some more experienced reefers.
    I have not contacted Aquacraft about their calibration fluid yet, I will. Through my research and own experience just from today, the quality control for their Refractometer calibration fluid appears to be sub-par. I mean, how can you let something like this important slip by? Had my salinity slowly crept up by a few more points, it could've crashed my system and I would have lost a lot of corals in the process.

    Definitely a lesson learned for me.
    What can you do to prevent this from happening? Triple check the calibration fluid with other devices via LFS, other reefers, etc... before depending on the calibration fluid. Even then, check with RODI water from time to time to ensure the value holds 0.
    Why don't we calibrate with RODI? You can.... but calibrating with RODI at 0 is far from what we are measuring at, so for the best accuracy, it's best to use calibration fluid.

    I'm curious now... who else is using Refractometer calibration fluid? Have you checked the accuracy of it?

    @stella1979 @grantm91 @Nanologist @LJC6780 @anarchy
    Last edited: Aug 4, 2017
  2. anarchyValued MemberMember

    Rodi before I got my rodi I just used tap water
  3. Nanologist

    NanologistWell Known MemberMember

    I use the Pinpoint branded one and now going to have it tested because of this! However, my water parameters have always matched what my LFS has seen. I keep it at 1.023 at the moment to acclimate everything since that's what my LFS keeps most of their stock at. Thanks for the heads up!

  4. grantm91

    grantm91Fishlore VIPMember

    DI water. I always aim for 1.025 for the simple reason id rather be under than over, for 2 reasons. Incase i go away and the tank doesn't get topped off. 2 incase I'm in-accurate i figured a little lower is always safer than a little higher. We all know I'm like mr basic. I feel like weighing my salt mixes gram for gram to see if it ever fluctuates through the eye of the refractometer as i think it would be a good experiment because the di water i use is the same every time and i trust it tbh. I just cba recording and weighing over the months I wouldn't trust my self or my eye.
  5. Nanologist

    NanologistWell Known MemberMember

    I completely agree. In a week I'm going to up it .001 and then after a couple more weeks up it one more to 1.025. I'm more concerned about Petal at this point since she was kept in 1.023. The inverts loved 1.025.
  6. grantm91

    grantm91Fishlore VIPMember

    I had that concern,
    But luckily the fish tank at the lfs i got the banggai was 1.026 i tested, i thought it would be lower but she obviously caters for typical reefers. I never really chat to her i just buy my water and thats it but them banggai were shiny . I couldn't fluctuate my salinity because of the nems i hear it would send them spastic, so mr majestic would have got a bucket drip acclimate at best but he just got temp due to the similar salinitys. He cool any way but your doing the right thing i reckon at your stage @Nanologist id probably do the same in a 10g with my first fish.
  7. Nanologist

    NanologistWell Known MemberMember

    Yeah have to make small changes in a small 10g!
  8. OP

    NartWell Known MemberMember

    So I wrote an email to Aquacraft asking about their QA for their calibration fluid.... I am kind of shocked about the response I got back for them. Debating whether I should post their response and reach out to Fritz again.

    Three main things this sales rep from Aquacraft said:
    1) each batch of their calibration fluid is matched against strict parameters of the scientific community
    2) I need to do a little research before I use Fritz salt and expose my tank to thousands of dollars worth of failure. As he says Fritz has thousands and thousands of negative reviews.
    3) switch to a better salt. Fritz is apparently low-grade stuff according to him
    Last edited: Aug 5, 2017
  9. KristaD

    KristaDValued MemberMember

    Thanks for this post! I have relied on you all for good info as I work through the saltwater process and you do not disappoint!
  10. grantm91

    grantm91Fishlore VIPMember

    Tell Fritz they will have the money to go deep in to this and will do if they bite at what is basically slander and i would if that was my product. i think I'm on a winner with my DI water lol. What are you calibrating with then? @KristaD @stella1979 @LJC6780
  11. stella1979

    stella1979ModeratorModerator Member

    Hmm, I've yet to double-check, (been spending my morning drafting a message to WWC about vermetids;)), but I think I have the same as NART. :( What a pita... I missed this thread yesterday and now I've got a batch of freshly mixed replacement water that may be off in salinity.

    Thanks so much for the head's up about this @NART . I'll double check everything tonight and let you know what I find.
  12. KristaD

    KristaDValued MemberMember

    I have been using a hydrometer (I know it isn't the best) but just ordered both a refractometer and a tds meter since I get my RO/DI water from the store. Thanks for the suggestion @NART
  13. OP

    NartWell Known MemberMember

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