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

[Miemaes]

Hey everyone,

I’m struggling with my magnesium levels straight from my freshly mixed bucket. I started using Instant Ocean when I gathered my first test kits. The day that I got my Salifert magnesium test kit I realized that it’s only at 1200ppm. I bought the Red sea salt (blue bucket)… and guess what… it also reads 1200ppm How is this possible? I’m mixing a new batch of water with my Instant Ocean salt according to the mixing instructions. I mixed it to match to 35ppt and it also reads correct on my refractometer. So it is not an issue due to incorrect salinity ratio. I mixed it for a minimum of 30 minutes… Ca 440 ppm KH 10 and Magnesium 1200. I havent measured my Red sea straight from the bucket yet but I’ve been only using that for my 33g and my Magnesium stays steady there too at 1200. Could it be a faulty salifert test kit? I’m so tired of constantly having to adjust my Magnesium every week in both aquariums with a minimum of a 100 ppm. Any advice or insight welcome. Thanks!

 

[Garf]

Hey everyone,

I’m struggling with my magnesium levels straight from my freshly mixed bucket. I started using Instant Ocean when I gathered my first test kits. The day that I got my Salifert magnesium test kit I realized that it’s only at 1200ppm. I bought the Red sea salt (blue bucket)… and guess what… it also reads 1200ppm How is this possible? I’m mixing a new batch of water with my Instant Ocean salt according to the mixing instructions. I mixed it to match to 35ppt and it also reads correct on my refractometer. So it is not an issue due to incorrect salinity ratio. I mixed it for a minimum of 30 minutes… Ca 440 ppm KH 10 and Magnesium 1200. I havent measured my Red sea straight from the bucket yet but I’ve been only using that for my 33g and my Magnesium stays steady there too at 1200. Could it be a faulty salifert test kit? I’m so tired of constantly having to adjust my Magnesium every week in both aquariums with a minimum of a 100 ppm. Any advice or insight welcome. Thanks!

It's only a little low if accurate, how are you calibrating the refractometer? Does the calcium and alkalinity match up to whatever the salt is supposed to be?

Edit - the test kit only needs to read 5% too low for your mag to be at 1280(ish), quite believable with our test kits to be honest.

 

[Miemaes]

It's only a little low if accurate, how are you calibrating the refractometer? Does the calcium and alkalinity match up to whatever the salt is supposed to be?

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?

 

[Miemaes]

It's only a little low if accurate, how are you calibrating the refractometer? Does the calcium and alkalinity match up to whatever the salt is supposed to be?

Edit - the test kit only needs to read 5% too low for your mag to be at 1280(ish), quite believable with our test kits to be honest.

My calcium read 440 and according to the package it should be 455. Magnesium should be 1345. Alkalinity is not displayed strangely enough

 

[Cichlid Dad]

Looks like you are using reef crystal. My new bucket I have been measuring 1200 mag @ 1.025. I don't know about the other brand. I Use a refractometer calibrated with calibration solution. I raise it with two part to my tank parameters

 

[Garf]

Is 1200 ok you think?

It wouldn't bother me, I expect everything is ok.

 

[Miemaes]

Looks like you are using reef crystal. Recently I have been measuring 1200 mag @ 1.025. I don't know about the other brand. I Use a refractometer calibrated with calibration solution. I raise it with two part to my tank parameters

I wanted to buy calibration solution but then I read different comments that every solution might result in different calibration. You know if this is true? Hence why I did a test batch per instruction on the bag to see how it matched up with my RODI calibrated refractometer.

 

[Garf]

I calibrate my refractometer with RODI water so it reads 0

You can make a standard solution out of table salt and RODI if you are interested;

 

[Miemaes]

It wouldn't bother me, I expect everything is ok.

I love to read this I feel the the inly thing I was doing was putting additives in my tank to chase that 1300 Magnesium. Then you add something and then it affects something else and before I know it I’m making a mess

 

[Miemaes]

You can make a standard solution out of table salt and RODI if you are interested;

Oh yes, I would love to try this. What are the ratios?

 

[Ziggy17]

What corals are you keeping?

 

[Garf]

Oh yes, I would love to try this. What are the ratios?

https://reefkeeping.com/issues/2004-06/rhf/index.php

 

[Miemaes]

What corals are you keeping?

A mix. Softies, zoa’s. LPS and SPS. I went a bit nuts buying all sorts of corals

 

[Cichlid Dad]

I wanted to buy calibration solution but then I read different comments that every solution might result in different calibration. You know if this is true? Hence why I did a test batch per instruction on the bag to see how it matched up with my RODI calibrated refractometer.

Our measurements are not 100% true. It is a matter of consistently. By a bottle of fluid use it to set your refractometer each use. Make sure your tank remains steady and when doing water changes you match the tank salinity. When you order a new bottle of solution just check it against the old bottle

 

[Miemaes]

https://reefkeeping.com/issues/2004-06/rhf/index.php

https://reefkeeping.com/issues/2004-06/rhf/index.php

Much appreciated. Will try this out for sure

 

[Miemaes]

Our measurements are not 100% true. It is a matter of consistently. By a bottle of fluid use it to set your refractometer each use. Make sure your tank remains steady and when doing water changes you match the tank salinity. When you order a new bottle of solution just check it against the old bottle

Thanks for the info and clarifying this.

 

[Ziggy17]

Animals love consistency. As mentioned in a prior comment, you’re probably just fine. I wouldn’t chase mag numbers unless you had a tank full of coral that really required high Mag. If your corals seem happy, then let r buck. And do weekly water changes to keep the mag up. Unless you’re noticing big uptake….

 

[Miemaes]

Animals love consistency. As mentioned in a prior comment, you’re probably just fine. I wouldn’t chase mag numbers unless you had a tank full of sps that really required high Mag. If your corals seem happy, then let r buck. And do weekly water changes to keep the mag up. Unless you’re noticing big uptake….

Every week I do a minimum of 10% water change. I’ll follow the advice on calibration here… and if it’s still 1200 I’ll see if I can just keep it stable around that and dose during the week if need be. Thanks!

 

[Randy Holmes-Farley]

RMM is looking better every day.

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

 

[Miemaes]

RMM is looking better every day.

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

I love this RMM principle already It is the one parameter that seems to fluctuate every time I test it. I re-tested the leftover water in my bucket and it was 1300. Checked after the WC a sample from my tank and that was at 1360 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. Thanks a lot for sharing this with me.