Importance of Mg?

[Aresangel]

Hello All, I am about 8 months in my salt water experience. I had a questions about the importance of testing for Mg? I have two test kids the Reef Master, and Salt Water master test kits from API. I can test for Ca, kH, Nitrates, Nitrites, Ammonia, Phosphates, and pH. I see some people posting their Mg measurements and wanted to know the importance of knowing that.

I know from my geology lessons that depending on the levels of Mg sea creatures can construct shells out of MgCa(CO3) instead of just CaCO3. Is magnesium is low or high what does that mean and how is that dangerous in a mixed reef.

I currently have the following:
Xenia, Candy Cane, Meteorite, Duncan, Red Cap, Birdsnests, Orange mushrooms, green tipped hairy mushrooms, feather dusters, zoothalids, clowns, gramma, golby, and snails and crabs.

Thanks for the advice!

 

[gone fishin]

http://reefkeeping.com/issues/2006-06/rhf/index.php

The link is an article on the relationship that exists between Magnesium, alkalinity and calcium.

The article can explain it better than I can. Basically you will want to test your magnesium along with the calcium and alkalinity. If you supplement for calcium and alkalinity then you will want to for magnesium as well.

 

[CStrickland]

Yeah, the article is better than I can explain either. Basically the mg keeps the ca and alk at the right levels, like it holds them in the water. So if mg drops, you can't keep them up.

 

[Sk8r]

If you are using kalk, you can depend on mg holding the readings for alk and cal locked, until the mg depletes. So testing the mg once weekly can assure you pretty well that things are ok. It IS well to run all three tests now and again, especially alkalinity, but with mg locked, the other 2 tend to be steady.

 

[Aresangel]

Ahh thanks all. Good article!

 

[Aresangel]

So what are some good readings for Mg? What should the range be etc? Calcium I try to keep around 420-480 and my alkalinity is normally around 10-11dKh

 

[jason2459]

What kind of reagents are you putting in or on your kids? Are they color changing? Mine are at times.

 

[jason2459]

So what are some good readings for Mg? What should the range be etc? Calcium I try to keep around 420-480 and my alkalinity is normally around 10-11dKh

I target
400 to 460 calcium
7-11 alk
1250 to 1350 Mg

Good guidelines
http://reefkeeping.com/issues/2004-05/rhf/

 

[Aresangel]

Awesome thanks! I will pick up a Mg test kit from my LFS! Thankfully I enjoy testing water it is somewhat therapeutic!

 

[jason2459]

Awesome thanks! I will pick up a Mg test kit from my LFS! Thankfully I enjoy testing water it is somewhat therapeutic!

Check the dates on the kit. Many times LFS bought kits are or near expiring. Also, many don't have Mg test kits.

I have not been impressed with red sea but they do have Mg kits and are appearing at more LFSs.

This is the brand I like and use as it was made for seawater testing and the owner occasionally visits our chemistry subforum.
http://premiumaquatics.com/products/salifert-magnesium-test-kit-2550-tests.html

 

[Aresangel]

Thanks for the heads up Jason, I will ask my fish store if they have any in stock, if not I will order that!

 

[Saltliquid]

Mag acts a carbonate, to over dose a little with mag is not bad thing!

 

[jason2459]

You won't want to increase it to much to fast.

 

[gone fishin]

For Mg I shoot for around 1350

 

[Mcgeezer]

Aim for 1350 as said.

Mg is the glue that allows Ca and Dkh to bind in order to form calcium carbonate. It is probably one of the more overlooked parameters.

 

[Isaacs55]

If you are using kalk, you can depend on mg holding the readings for alk and cal locked, until the mg depletes. So testing the mg once weekly can assure you pretty well that things are ok. It IS well to run all three tests now and again, especially alkalinity, but with mg locked, the other 2 tend to be steady.

+1

best explination right here. No better way to explain unless you read the link to reefkeeping.com

 

[rt67ghy]

Thankfully I enjoy testing water it is somewhat therapeutic!

I agree, especially when you find your tests showing what you expect to find regarding the levels you aim for.