Inaccurate test kits?

Discussion in 'Water Chemistry' started by Va Reef, Jun 8, 2015.

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  1. Va Reef

    Va Reef Giant Squid

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    Been daily monitoring my big 3, and notice some discrepancies recently. The last week my calcium started at about 465ppm, mag at around 1350-1400ppm and alkalinity at around 3.5 meq/L. I realized my alk was low for the calc and mag levels so I dosed some bright well alkalin buffer to raise it to about 4.2 meq/L over two days. The night before last I tested my magnesium, it showed at 1200, a 200ppm drop from the previous night. Calcium was at 440ppm, and alkalinity was 4.2. Naturally I dosed the recommended amount to raise it 100ppm, and tested an hour after drip dosing it at 1295ppm. Today, my calcium is at 430ppm (usually only lose 5ppm/day) and mag is back down to 1200, while alkalinity dropped to 3.5. Through all of this pH has stayed stable at 8.3. I decided to check my salt (hydrometer, checked multiple times a year against a refractometer, I trust it to be accurate) and it came back as 1.0225. Will this lower salt be causing the weirdness in my big 3? Tank is a 34g solana, over 40 different sps pieces (wild cut, maricultured, and aquacultured) and a couple acans and gorgonians. Everything looks great, growth has been amazing, pe is awesome, even on fresh cut wild colony frags. I just don't understand it. I do dose daily 1.5mL of acropower and usually a few drops of boron solution, to maintain boron at about 7ppm. I will be dosing balling method on my 3 part dosing pump once I get my daily uptake values figured out.
     
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  3. Billme

    Billme Eyelash Blennie

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    You might be able to figure out the consistency between tests by taking multiple tests immediately after the other. That way you'll know that the approximate same perimeters exist in the water you're testing. You can also approximate the accuracy range of the kits.
     
  4. Va Reef

    Va Reef Giant Squid

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    So do tests multiple times? I triple checked my mag yesterday at 1200 each time and again now when I also got 1200. They're Red Sea test kits.
     
  5. Va Reef

    Va Reef Giant Squid

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    Also, for sps systems, what is a reasonable amount of daily loss of the big 3? Seemed to be about 5ppm calc a day and 15-20ppm mag a day. Couldn't get a reliable uptake value for alkalinity.
     
  6. Billme

    Billme Eyelash Blennie

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    If your question is if the kits are accurate, that's the quickest way I can think of to test them.
     
  7. Va Reef

    Va Reef Giant Squid

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    I guess it's more of a "is it possible my test kits are funky or is it really dropping 100-200ppm back down to 1200 a night?"
     
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  9. Billme

    Billme Eyelash Blennie

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    Sounds like you've done due diligence on testing the magnesium kit. That is a curious amount for magnesium to drop.
     
  10. Corailline

    Corailline Super Moderator Staff Member

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    Out of all the test kits I think mag is the one most prone to error. I use the Salifert kit, it seems to be fairly consistent, but you have to be spot on with your measurements.

    You must adjust your salt value to your target. Get that figured out and proceed from there.

    Mag stay consistently high for me, I rarely test for it because typically utilization is just that low.

    As Billme posted, you're not going to be sure until you test the values you got against other test kits or methods.
     
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  11. Flaring Afro

    Flaring Afro Purple Spiny Lobster

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    I know API test kits have an expiration date on them. Have you checked for one?
     
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  12. Corailline

    Corailline Super Moderator Staff Member

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    It is a dry heat, yeah right !
    Which bailing method are you looking at?