Magnesium has a constant low reading of 1200 (both instant ocean and red sea) - help!

BeanAnimal

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I calibrate my refractometer with RODI water so it reads 0 and did a test batch of mixed salt water per instructions on the bag (exactly 1 galon of RODI mixed with 1/2 cup of salt) and it measured exactly 35ppt. Is 1200 ok you think?
...welp everyone already gave you the same advice I posted without reading ahead. You are in good hands.
 

ReeferZ1227

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The old salifert kit had a dropper and a powder and the reagent.

The new kit is just dropper and reagent.

I had a huge discrepancy with the new kit, greater than 100ppm.

I use salifert for everything but phosphate, but i trashed their magnesium kit and went with the nyos for mag.

I would recommend an independent test from a friend or LFS to confirm your findings or try nyos.

Another note: magnesium is not swinging 100ppm each week, your test kit is, or your salinity is. I had similar issues to you early on, and a rough time with a red sea refractometer. I went with pinpoint salinity monitor and hardly ever touch mag now, minor corrections here and there.
 
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Miemaes

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The old salifert kit had a dropper and a powder and the reagent.

The new kit is just dropper and reagent.

I had a huge discrepancy with the new kit, greater than 100ppm.

I use salifert for everything but phosphate, but i trashed their magnesium kit and went with the nyos for mag.

I would recommend an independent test from a friend or LFS to confirm your findings or try nyos.
Yeah I have the old kit. It’s hard to also scoop that powder out of the bottle. I bought phosphate and nitrate from them too… but I think I’m too color blind to use it accurately The shifts in saturation of color are ridiculously small and hard to catch. I go through every room of my house to check the result under different lights and I’m still as confused at the end as I was at the beginning. I think I’m giving Magnesium the cold shoulder for a while. When I’m ready I’ll check into Nyos. Thx!
 

ReeferZ1227

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Yeah I have the old kit. It’s hard to also scoop that powder out of the bottle. I bought phosphate and nitrate from them too… but I think I’m too color blind to use it accurately The shifts in saturation of color are ridiculously small and hard to catch. I go through every room of my house to check the result under different lights and I’m still as confused at the end as I was at the beginning. I think I’m giving Magnesium the cold shoulder for a while. When I’m ready I’ll check into Nyos. Thx!
Phosphate use a hanna checker if youre growing coral.

Nitrate is pretty dang good, essentially you just want to look through the side and see some slight pink, my tank runs 1-2.5ppm. I periodically add nitrate, but i really only test to make sure its not bottomed out, i dont really take any action on the result. If you dont see any looking through the side, buy some food grade sodium nitrate (amazon) and dose. Dont do any crazy swings but you can add 1-2ppm per day, just dont be 0.
 
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Phosphate use a hanna checker if youre growing coral.

Nitrate is pretty dang good, essentially you just want to look through the side and see some slight pink, my tanj runs 1-2.5ppm. I periodically add nitrate, but i really only test to make sure its not bottomed out, i dont really take any action on the result. If you dont see any looking through the side, buy some food grade nitrate and dose. Dont do any crazy swings but you can add 1-2ppm per day, just dont be 0.
Ok, I’m going to do this the way you suggest after dinner. I feel I keep looking at it until I wanna see pink… but then again it looks colorless you know?! I think mine are very low the times I’ve tested. Both phos and nitrate
 

ReeferZ1227

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Ok, I’m going to do this the way you suggest after dinner. I feel I keep looking at it until I wanna see pink… but then again it looks colorless you know?! I think mine are very low the times I’ve tested. Both phos and nitrate
You put the white card behind it under daylight (not your tank blues, or if you have hihats with bright white). If you dont see it, you dont see it. Buy some food grade sodium nitrate, use a calculator and dose. Confirm you can see it, then decide if you want to feed more, cut back on filtration, or dose nitrate. Anything besides no pink on the test lol.
 
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BeanAnimal

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I still got your post via e-mail notification and I’m putting in an order for the Hydrometer. Very helpful info, so thanks!
Salinity is somewhat relative if you keep it consistent and use the same device to measure your system and what you are acclimating to it. There is no "perfect" number but the hydrometer gives you the ability to actually know what you are reading and gives you a single point of truth to calibrate other devices from. It is not a must have tool, but it is a nice tool if you can afford it.
 

KrisReef

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Another helpful tip for consistent water measurements is to get a syringe to pull the water samples for your test kits. It can reduce/ remove one source of sampling error by making each sample the same each time.

It can make it easier to get repeatable results once you get used to using one.
 

Randy Holmes-Farley

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But I have to say… I notice when you draw liquid out of the bottles for salifert… the amount of air that is included also deviates every time. A little bit more or less also makes your reading different. I am so freakin tired of Magnesium all together I’ll probably let it be as I change water weekly and will add a small amount when I dose Calcium.

Just a comment on that which concerns me. Be sure you are reading the syringe correctly and are ignoring the air entirely:

 
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Miemaes

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Just a comment on that which concerns me. Be sure you are reading the syringe correctly and are ignoring the air entirely:

Just a comment on that which concerns me. Be sure you are reading the syringe correctly and are ignoring the air entirely:

I had missed the link. Sorry about that. Thanks for clarifying and all your shared information It’s all super helpfull
 
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KrisReef

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The tips are variable in volume so you just read the barrel being careful to avoid bubbles in the liquid when you draw the barrel back to the volume you are using.
 
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Miemaes

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Another helpful tip for consistent water measurements is to get a syringe to pull the water samples for your test kits. It can reduce/ remove one source of sampling error by making each sample the same each time.

It can make it easier to get repeatable results once you get used to using one.
I’ve been using the ones included with my salifert kit. How much it draws water is pretty accurate I think. It’s the one that draws the reagent with the pink tip that I find somewhat inconsistent at times. I might be just nitpicking here The amount of air that is in there varies as well at times. You don’t account for the air… but you still measure your results based on how much your plunger goes up or down to get the color change. Like how much air should these pink tips hold exactly? Especially when there is little liquid left in your bottle where you have to tilt and run the risk of accidentally sucking up a bit more air… it’s good to know how much air exactly is accounted for in this test. Or am I having a dumb moment here?
 

KrisReef

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Ignore the air. Just be careful to allow the liquid time to be drawn into the syringe and the liquid volume will be the number shown on the barrel.
 

ISpeakForTheSeas

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Just a comment on that which concerns me. Be sure you are reading the syringe correctly and are ignoring the air entirely:

Just adding the link to the exact post (#83) where the reason for ignoring the air in the syringe (like KrisReef mentioned above) is explained:
 
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Miemaes

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Just adding the link to the exact post (#83) where the reason for ignoring the air in the syringe (like KrisReef mentioned above) is explained:
@Randy-Holmes is definitely my new reef guru I think it’s amazing when ppl go out of their way to share their knowledge with folks like me who are sometimes overwhelmed with the hobby. Makes all the difference between giving up or pushing through
 

ReeferZ1227

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@Randy-Holmes is definitely my new reef guru I think it’s amazing when ppl go out of their way to share their knowledge with folks like me who are sometimes overwhelmed with the hobby. Makes all the difference between giving up or pushing through
I am still blown away that an inventor of human pharmaceuticals still shows up for decades to answer the same "why is my pH low?" question. What a lesson in humility.

I think your issue is as simple as variances/calibration issues from inaccurate measurements lead to a lack of confidence in other measurements. I remember that stage. Invest in the right tools if youre going to invest in coral and invest into your understanding why the measurements matter and inter-dependencies for each of the things your measuring, most easily done with RHF literature.
 
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exnisstech

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I calibrate my refractometer with RODI water so it reads 0 and did a test batch of mixed salt water per instructions on the bag (exactly 1 galon of RODI mixed with 1/2 cup of salt) and it measured exactly 35ppt. Is 1200 ok you think?
I would get or make some calibration fluid. May not be worth it to you but I recently added a TM precision hydrometer to verify my salt mix. I have refractometers and a Hanna salinity tester but they all need calibration. The Hydrometer doesn't lie as long as the temp is correct so I trust it 100 %.
Getting 35ppt out of 1/2c to 1 gal water seems off to me. I've been using reef crystals and regular IO for years and have never had 1/2c yield 35ppt. I mix 28 gallons at a time and have to use 16 cups of salt to get 1.025 (its how I prefer to measure) my math sucks but that's 32 half cups for 28 gallon of water. I would verify your refractometer is accurate.
 

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I’ve been using the ones included with my salifert kit. How much it draws water is pretty accurate I think. It’s the one that draws the reagent with the pink tip that I find somewhat inconsistent at times. I might be just nitpicking here The amount of air that is in there varies as well at times. You don’t account for the air… but you still measure your results based on how much your plunger goes up or down to get the color change. Like how much air should these pink tips hold exactly? Especially when there is little liquid left in your bottle where you have to tilt and run the risk of accidentally sucking up a bit more air… it’s good to know how much air exactly is accounted for in this test. Or am I having a dumb moment here?
Make sure the pink tip is fully seated. If it not and its above the level of the liquid, you can pull air in from around the connection point. This was a huge problem with one of the Hanna kits I had.
 

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