Low Magnesium...

[kzziboy]

I finally got a Magnesium Test Kit. Just as I thought, my readings are low.
I measured a reading of 920 last night. I wanted to do it again just to make sure I did it right...probably do that tonight.

Anyway, my question is what type/brand of Magnesium is best to dose? I've NEVER ever dosed this stuff before.
How long should it take to bring it up where its supposed to be?

Thanks!

 

[a.browning]

I have always used the bulk chemicals from Bulk Reef. They are cheap and easy to mix up. You could use Kent or similar from the store but it'll cost a lot more. With magnesium, it takes a lot of solution to raise it up. If this is for your 55g in your sig, you will need a little over 1600mL of solution to raise it up.

Or you could do a few large water changes, however, if your magnesium is that low I would question your salt mix. I can't see how it would drop that low. Even in my full sps reef I have never had to dose magnesium, IO salt mix keeps it up high.

 

[downbeach]

What kind of salt mix are you using?
What is your salinity?
What do you use to test it? Is it calibrated?
What are your other parameters?

 

[kzziboy]

I use instant ocean salt mix..not Reef Crystals...
Salinity shows 1.025 with two different hydrometers...I don't have a refractometer.
Other parameters:
Calcium: 340
PH: 8.0-8.1
Phospate: Zero...as far as I can tell from a test. I run a sump with chaeto...
Nitrates: Zero

The only thing besides the 5 fish I have in the tank is pulsing Xenias.
I have 1 Royal Gramma, 1 Green Chromis, 1 yellowtail Blue Damsel, 1 Blue Damsel, and 1 I think percula Clownfish....I got it from someone who was moving.
There's about 60 or 70 lbs of Live Rock in the tank and a DSB in the sump.
I have all kinds of pods in the sump...pretty unbelievable.

 

[Mavrk]

Test your newly mixed saltwater and see what the readings are. Unless you are using IO from a few years back, the magnesium should be over 1300. What test kit are you using? Are you sure you read it correctly (sometimes people read the numbers upside down in Salifert test kits for instance).

 

[downbeach]

If you're considering the addition of something to your tank, I think it would be a good time to get a better method of testing your salinity, a refractometer and calibration solution would be a good idea. I'll bet your salinity is actually lower than your hydrometers are indicating and as a result so is your Ca and Mg. Have you tested Alk? What are you using for test kits?
It appears that you don't have any real demand for higher levels of Ca, Alk and Mg, at this time, but it would be a good idea to know what they are and why and when they will become more necessary. So now would be a good time to make sure you get some testing kits/devices that will give you the type of accuracy you will need to make decisions on when and how much to dose.

 

[kzziboy]

I just got a Salifert Magnesium Test Kit...
First time I've used one. I'm pretty sure I did it right. I will re-test. Any tips on a Salifert?
It's good through 2013...
YES, I do want to get a refractometer. Anybody got a deal on one??!!
No, I haven't tested for Alkalinity lately...
I have API test kits for Phosphate, PH, Nitrate, Nitrite, Ammonia, Alkalinity, and Calcium.

 

[Mavrk]

Tips on salifert... make sure you use the tip haha. That is to say make sure you have the tip on the end of the syringe. There will be air inside the syringe, but that is already calculated in. I didn't think about it earlier, but if you didn't use the tip then your numbers will be quite a bit lower.

Also, end point is as soon as the color changes. Not when it becomes a certain shade of whatever. But I suspect that is not the issue. How old is your salt?

 

[Wet Dreamer]

I just put a post on the other low magnesium thread, as I am having the exact same issues but with Reef Crystals though! I have never had issues in the past with keeping my mag levels up, but since I switched to reef crystals my mag dropped to below 1000, I have been struggling to get it back up since.

 

[kzziboy]

Salt is only about 4 or 5 months old....Big Bucket O Instant Ocean...
I'll test a new mix.
Yes, I do have the "tip" for the syringe.
So, to make sure I have this right...
AFTER you mix everything in the vial, you drip 1 drop at a time and swirl the solution to mix it....then your reading is whatever it's at right when you get a color change...
So, if you go by the chart on the instructions...if you have .38 of solution left in the syringe when the color changes, then your magnesium level is 930 right?
I'm assuming you have the same test kit...

 

[downbeach]

In all the years I've been in this hobby, I've never had to dose Mg. So, I'd be more suspicious of a test kit, or possibly low salinity issue. I also use RC. So, I think first you should make sure of the accuracy of your salinity, since if it's low, so is your Ca and Mg. Which is why you would need a calibrated refractometer.
Good, reliable, accurate test kits will go a long way to help you resolve problems and get an understanding of the chemistry needed in this hobby. Salifert is one of those kits.
There has been some anecdotal evidence of salt mixes contained in a plastic bucket, having had some of the elements separate into their elemental grain sizes due to vibrations during shipping, so although that may be a remote possibility, if you bought your salt mix in a bucket, it might be prudent to re-mix the contents.

 

[kzziboy]

It is in the bucket...
I'll be sure to shake it up a bit.
Next thing I will do is get a refractometer.

Thanks!

 

[daninflipflops]

Salt is only about 4 or 5 months old....Big Bucket O Instant Ocean...
I'll test a new mix.
Yes, I do have the "tip" for the syringe.
So, to make sure I have this right...
AFTER you mix everything in the vial, you drip 1 drop at a time and swirl the solution to mix it....then your reading is whatever it's at right when you get a color change...
So, if you go by the chart on the instructions...if you have .38 of solution left in the syringe when the color changes, then your magnesium level is 930 right?
I'm assuming you have the same test kit...

not sure on Salifert, but if its like red sea tests i use, the charts are based on the amount of titrant USED, not left. on my test, you start with 1.0 ML and figure out how much you used. in your example of 0.38ml left, that means you used 0.62ml (i.e. 1.0 minus 0.38). check your instructions

 

[daninflipflops]

not sure on Salifert, but if its like red sea tests i use, the charts are based on the amount of titrant USED, not left. on my test, you start with 1.0 ML and figure out how much you used. in your example of 0.38ml left, that means you used 0.62ml (i.e. 1.0 minus 0.38). check your instructions

out of curiosity i went and looked up the salifert mg test, they do it differnt than red sea, so sounds like you did the test right...disregard my ignorant post:spin3:

 

[kzziboy]

Yeah, I looked at it again and I think I did it right.
When I have more time tonight I'll re-test it.
Question...
On those syringes...do you have to rinse them out? OR should you just leave them be?
Especially the small 1 ml syringe. What do you do with the solution that is left over at the end of your test? Do you squirt it back in the bottle or dispose of it?

But again, should you rinse out the syringe when you're done?

Thanks again as always!

 

[Mavrk]

Sounds like you are doing the test correctly. I will be virtuous to see if the second test shows the same and what your new water reads. Like mentioned above, you might want to roll the bucket to mix it up a bit. Also, if the test kit express in a year, then it is a couple years old. Do you know how it was stored? Or is this just one you bought a while back. I would have the LFS check the Mg before dosing since the kit is not new.

 

[Peter Eichler]

So, what did you get?

If you get that same reading again I would be highly suspect of the accuracy of your test kit.

 

[bertoni]

I'm skeptical about that test result as well, assuming the SG is normal. I'd do some double-checking before doing anything drastic.

 

[kzziboy]

I think before I do anything drastic, I'll get a refractometer. I want to make sure of my salinity.
Unfortunately, I don't have a decent LFS within 100 miles. Gotta love South Dakota.

 

[downbeach]

I think before I do anything drastic, I'll get a refractometer. I want to make sure of my salinity.
Unfortunately, I don't have a decent LFS within 100 miles. Gotta love South Dakota.

Put some calibration fluid on that order.