Magnesium

[madasahat]

Hi

First time posting but have had a tank for a while. Just thought i would test my mg and its 30 ??? according to the calculator thats nearly 2kg of epson salts could this be correct? 220lt tank . i have started dosing very slowly but strangely i mixed 1 kg of epson salts with 1 ltr of water and added a few drops of the mix to my salifret test kit and it didnt make any difference ?

Regards

 

[redfishbluefish]

First off, welcome to R2R. It can't be 30! What salt are you using and what test kit to measure Mg?

 

[Reefnoobz90]

Something's wrong with your test kit or maybe you tested wrong. I'd double check, bring some water to the LFS and have them test it

 

[redfishbluefish]

Just thought of another question.....What is your target salinity level, and what do you use to measure SG?

I am not aware of any commercial salt with a magnesium level of less than 1200 ppm.

 

[vetteguy53081]

Totally impossible. Do you have actual MAG that you can use your test kit to check? Also if you have a friend with a mag kit, have them check for you to compare.
What test kit are you using?? API has been known to give false results.

 

[MnFish1]

It must be an error in your test (unless its a freshwater tank lol jk). I would not dose anything into your tank without re-verifying the result. I guess another possibility would be a salt mix which mistakenly had no Mg in it (but I'm not sure this makes sense)

 

[maroun.c]

Definitely something wrong with your kit, I would test with another kit to verify.

 

[madasahat]

i just bought the kit its a salifret and in date using coral sea pro just run a test on a new mix of water and same result so ether 1. i cant read 2. the test is faulty 3. they forgot to add it to the salt

If i carry on adding a few drops more than in one syringe it changes colour

 

[redfishbluefish]

I think I discovered the error.....when you said something about needing to add more than 1 ml. You're reading the syringe wrong....that is, instead of just reading the number on the syringe and comparing it to the chart, you've taking that reading and subtracted it from 1, so that you came up with 0.98 mls, which equals 30 ppm. I believe your syringe actually read 0.02, and looking at the Salifert table, that equals 1470 ppm. Yes, you used 0.98 mls, but Salifert doesn't want you doing that complicated math of subtracting from 1, so you just need to find the actual syringe number on their table!

 

[madasahat]

DOH !!!! you are right teach me to read the instructions more carefully lol thank you for your help

 

[MnFish1]

i just bought the kit its a salifret and in date using coral sea pro just run a test on a new mix of water and same result so ether 1. i cant read 2. the test is faulty 3. they forgot to add it to the salt

If i carry on adding a few drops more than in one syringe it changes colour

I don't use this test (any more) - but I remember that its easy to misread the value on the syringe - i.e. the wrong way.
on that test - a level of 30 would be 0.02 cc of reagent used. Which would be 1470 if read the other way - here is a video

 

[madasahat]

you are a life saver lol

 

[MnFish1]

I think I discovered the error.....when you said something about needing to add more than 1 ml. You're reading the syringe wrong....that is, instead of just reading the number on the syringe and comparing it to the chart, you've taking that reading and subtracted it from 1, so that you came up with 0.98 mls, which equals 30 ppm. I believe your syringe actually read 0.02, and looking at the Salifert table, that equals 1470 ppm. Yes, you used 0.98 mls, but Salifert doesn't want you doing that complicated math of subtracting from 1, so you just need to find the actual syringe number on their table!

To make it even more confusing - they also say (in the instructions take the number (lets say .02) - use this equation 1 minus the number = 1 - 0.02 = .98 - multiply by 1500 = 1470..... So its easy to do both and then look at the chart.