Low magnesium in Instant Ocean Reef Crystals

JACK50REEF · Apr 4, 2016

I have been using reef crystals for my reef tank. I tested a new batch of saltwater at 1.024 salinity.

Alkalinity -10.5 dkh
Calcium -450
Magnesium-1150

My reef tanks magnesium is 1350.

Should I dose the batch of fresh saltwater with magnesium before doing my water change?

JACK50REEF · Apr 4, 2016

The alkalinity, calcium and magnesium mentioned above are the results from the new batch of saltwater.

JimWelsh · Apr 4, 2016

Have you repeated and confirmed the Mg results on the new batch of saltwater? If so, have you also repeated and confirmed the Mg results on the display? Just trying to make sure this isn't a testing error.

JACK50REEF · Apr 4, 2016

Yea. The results were repeated and accurate. I dosed the new batch to 1350.

JACK50REEF · Apr 4, 2016

I use salifert fyi

JimWelsh · Apr 4, 2016

OK, good to know. FWIW, I once had a batch of regular IO that had crazy high Mg. As fate would have it, this batch coincided with me getting a new Salifert Mg test kit. At first, I concluded that the test kit was bad, and demanded a replacement from the vendor, who complied. When the new Mg test kit also gave the same reading, that's when I figured out that it was the salt, and not the test kit, that was off.

JACK50REEF · Apr 4, 2016

Yea. I am returning the salt mix and investing in redsea. I heard it really good. Have you ever used brightwell? I dosed an hour ago. Will it keep on rising? Should i let the new batch keep mixing?

JimWelsh · Apr 4, 2016

JACK50REEF said:
Yea. I am returning the salt mix and investing in redsea. I heard it really good. Have you ever used brightwell? I dosed an hour ago. Will it keep on rising? Should i let the new batch keep mixing?

OK. OK. No. OK. Dunno, test again and see. Wouldn't hurt.

redfishbluefish · Apr 4, 2016

Did you mix the dry salt before measuring out the salt to mix with water? It could be that the small stuff settled out and simply needed to be mixed. If it's a bucket, put it on its side and roll it around for a bit.

JACK50REEF · Apr 4, 2016

Yea. I shake the bag up really well. I do that every week I do a water change. I mix it really well the first time I buy the salt mix as well.

Randy Holmes-Farley · Apr 5, 2016

Let us know what you find with the new mix since I still think it a reasonable chance it is testing error of some sort (magnesium, salinity).

Randy Holmes-Farley · Apr 5, 2016

Bear in mind that upping the salinity to 35 ppt (sg = 1.0264) will boost the magnesium to 1265 ppm, and that is likely within the test kit reproducibility of 1280 ppm which is what natural seawater would read at 35 ppt.

McMullen · Apr 5, 2016

I've used IO reef crystals and rarely dose Mag as it maintains around 1360-1380. Every now and the I'll have to add a little Mag from DT reading 1340. But I don't think I've ever seen it lower than that.
Not sure how much difference it makes but I don't test the salt mix, simply test water day after a water change.

120reefkeeper · Apr 5, 2016

Not recently but in the past I've had the same issue with IO Reef Crystals. Originally this is what got my attention about Magnesium.

Waters · Apr 5, 2016

I have always dosed Mg in my new batches of Reef Crystals for the same reason.

TheEngineer · Apr 5, 2016

Also wondering when you last calibrated your refractometer (assuming you are measuring with one). What is your DT running at?

Midasreefs · Apr 5, 2016

My IO reef crystals is very low in magnesium too, last batch was about 1050, and all my previous batches were around the same. I think I'm going to try RedSea salt next time...

cj in sac ca · Apr 5, 2016

Ok I'm new to the hobby. Can some one give me the basics of what my numbers should be for everything.
My salinity is around 1.25
I'm in a 30 tall with some green star polyps and some blue Zoas/ poalys I want to add more but want to make sure all my parameters are correct.
Thanks for the help

jason2459 · Apr 5, 2016

cj in sac ca said:
Ok I'm new to the hobby. Can some one give me the basics of what my numbers should be for everything.
My salinity is around 1.25
I'm in a 30 tall with some green star polyps and some blue Zoas/ poalys I want to add more but want to make sure all my parameters are correct.
Thanks for the help

Recommended parameters
http://reef2reef.com/threads/optima...-reef-aquarium-by-randy-holmes-farley.173563/

And a collection of salt mix parameters that can give a very general idea of what to expect from different salt mixes. There is no "best"
http://reef2reef.com/threads/saltmix-parameters-bring-on-the-test-results.233233/

cj in sac ca · Apr 5, 2016

jason2459 said:
Recommended parameters
http://reef2reef.com/threads/optima...-reef-aquarium-by-randy-holmes-farley.173563/

And a collection of salt mix parameters that can give a very general idea of what to expect from different salt mixes. There is no "best"
http://reef2reef.com/threads/saltmix-parameters-bring-on-the-test-results.233233/

Thank you so much this will be a great help