Magnesium

[benray4fun]

How many of you reefers dose magnesium on a regular basis?... "especially you sps freaks." And how important is it?...

I don't currently have a test kit for it or a dosing scheme, but I'm assuming I'll have to get with it soon as all my sps is looking pretty sad...

I can get everything to grow, but my sps is refusing to budge and some are even bleaching...

 

[argi]

While I have never really dosed magnesium in my tank I am going to start, but actually for a different reason. I have a small outbreak of bryopsis and some people have had luck getting rid of it with elevated levels of mg (http://www.reefcentral.com/forums/showthread.php?s=&threadid=1113109).

What are you other parameters such as alk, calcium, salinity, nitrates, phosphates and pH?

Are they bleaching from the top down, bottom up or random areas?

 

[argi]

Also forgot to mention it could be an issue with competition between corals. Do you have lots of leather corals in the tank?

 

[Shark Bait100]

I dose mag to boost IO salt. I add it directly to the make up water. I use randy's recipe with mag flake. i found that when ever my mag levels get down below 1100, I start having sps trouble like stn, and poor polyp extention and color.
Some parameters on your tank and how they are bleaching would help diagnosis your problem. If you are running a mix reef, are you running a good quality carbon 24/7?

 

[bpd964]

I use it in my calcium reactors second chamber. I've been using it for a few months and it seems to make my SPS PE more pronounced and coralline is seriously out of control.. My calcium is in the 450/500 range, alk 3.5 and mag is in the 1300's and rock steady.. I don't drip kalk or anything else.. Ph is steady at 8.2 and doesn't move even when the lights are out in the display.

 

[MADtanks]

damn i stopped using my carbon bc i lost some of my corals when i decided to changed out the whole reactors worth of carbon out

 

[Obi-dad]

Get an Mg test kit, unless you do a lot of water changes. Especially if you are using a 2-part to keep up ca and alk levels, as the Mg will slowly decrease using a 2-part system. I think not as critical with Ca reactors as some of the Ca media contains Mg.

 

[bpd964]

<a href=showthread.php?s=&postid=10094736#post10094736 target=_blank>Originally posted</a> by erickrm
damn i stopped using my carbon bc i lost some of my corals when i decided to changed out the whole reactors worth of carbon out

I would go back to using carbon if you have a mixed reef that have any type of zoa's or mushrooms.. Just make sure you replace it on a regular basis..

 

[MADtanks]

sorry to hijack thread but how much of the carbon should i change say like me i have two little fishes reactors, and i filled it about half way with carbon, and the phosban i fill less than half way.

 

[pecan2phat]

I find that Mag drops faster than alk or Ca.
I test weekly and add magflake to adjust up to 1350 ppm.

 

[bpd964]

<a href=showthread.php?s=&postid=10094808#post10094808 target=_blank>Originally posted</a> by erickrm
sorry to hijack thread but how much of the carbon should i change say like me i have two little fishes reactors, and i filled it about half way with carbon, and the phosban i fill less than half way.

Do you use it together in 1 phosban reactor or do you use it separately in two different reactors?

The carbon needs to be changed more frequently than the phosban so I would use the phosban in one reactor and either put the carbon in a high flow area in a mesh bag or a separate reactor. I have an extra reactor if you want it so you can change your carbon every 1 or 2 week as not to dusturb your phosban..

 

[ctreefer]

Pecan2phat,

That’s interesting that you are having a similar problem as mine. My Magnesium seems to move quicker than my Calcium. I’ve read that in coral growth some of the Mg will bind with carbonate. I’m guessing that for some reason in my system the corals are uptaking the magnesium much more than the average system offsetting the consumption of Calcium. I have to test Magnesium every other week to make sure I’m above 1200ppm.

 

[Obi-dad]

<a href=showthread.php?s=&postid=10094821#post10094821 target=_blank>Originally posted</a> by pecan2phat
I find that Mag drops faster than alk or Ca.
I test weekly and add magflake to adjust up to 1350 ppm.

From a post by Randy HF -

In the last article linked below I show that the depletion rate from calcification ought to be on the order of 10-200 ppm per year. 50 ppm per week is not coming from coral use. (this paragraph is in reference to magnesium)

Coral skeletons and coralline algae contain about 8-1000 times less than magnesium than calcium. So if calcium depletion is 100 ppm per week, then magnesium ought to be on the order of 0 to 12 ppm per week.
...

I don't really see where the magnesium could be going. Even if it were getting sucked into pure magnesium carbonate or hydroxide, that would use up 23 dKH of alkalinity for each 100 ppm of calcium. Presumably you are not even adding that much, aside from the limewater.

That is why I am suspicious of it being real as opposed to a measurement or water change issue.


I wonder why you are seeing so high a Mg loss since it probably isn't due to coral uptake?

 

[pecan2phat]

ctreefer,
I recently moved up here and restarted some of my tanks back up and although salts are lacking in magnesium, my reef setup when I was down in Long Island, needed both magnesium and strontium supplementation at least weekly.
I've pretty much given up on Seachem's mag supplement due to the amount I was using to keep the level in the 1300's. Magflake and the "reef chemistry calculator" works well.
I do sometimes wonder if this "raw" method fuels algae growth though
Interestingly enough though with Reef Crystals, I found it to be low in Mg (around 1080 ppm) see thread ------> http://www.manhattanreefs.com/forum/general-discussion/24970-instant-ocean-vs-reef-crystals.html

In a nutshell, after tank stabilized, my Ca & Alk was pretty much rock solid with a CaRx but Mag & Stontium needed constant dosing.
I've also read somewhere that with low Mg, it affects how the corals use Ca & Alk.

 

[Obi-dad]

pecan2phat, how often are you doing water changes? Since your salt is low in Mg, that explains the dropping Mg much better than coral uptake.

 

[pecan2phat]

Greg,

It seems to happen to a lot of SPS tanks when I was part of LIRA. Magnesium depletion was always so prevalent that 3-4 cups of magflake per week was the norm.

 

[pecan2phat]

Greg,
When my tank was up and running in LI, I averaged 20% water change every 2 weeks. That was because I had a high fish load, with my setup here, I'll probably drop it to 20% per month depending on the nitrates and phosphate readings.

I migrated through a bunch of salts over the years but eventually ended up going back to IO. With each newly made batch of RO/DI water, I would first spike the water with about 9 teaspoons of magflake, let mix, then add the salt. This was to address the salt issue but I still needed to bring the Mg up about 50-80 ppm after each weekly water test.

 

[Shark Bait100]

I think Greg hit it right on the head. Most salt mixes out there are low on mag and alk, and some sort of supplement is needed, or you will be loosing mag/alk each time you do a water change. That is why you should mix it into your make-up water at water change time.

 

[ctreefer]

pecan2phat,

I'm not really sure why it is depleted so quickly, but it doesn't just affect my sps tank. I have a FOWLR that has been set up since December and for the hell of it I checked the magnesium about 2 months ago and it read around 600. I was doing in the range of 20-30% water changes per month and little to no coralline was in the system so I'm not sure where it was going unless my IO is somehow that low. (I'm using a new batch now so no way of testing the previous.) I had to add if I recall over 1 gallon of Randy's magnesium solution to get it to 1100 so I could get some coralline growing.

 

[benray4fun]

Guys,
I haven't taken any readings in a minute because my tank is very stable and all my parameters are within range every time I test, so I slowed down on my testing. I only test when necessary now or occasionally.

My problem started when I got some rare sps frags from a friend and watched them bleach then brown out over a couple of months. I took readings and everything was normal..."I couldn't figure it out as I never really dealt with sps corals before."

I called my buddy up and he said that without proper magnesium my
calcium and ph would drop and indeed they did, my ph went south to 7.8 so I added some buffer to get it back up. My calcium never goes down, it just doesn't and I'm glad for that. As far as the magnesium, I started dosing with purple up as it has magnesium, strontium and more calcium, but I don't know the values as I have no test kit for now. I'm quite sure I'm low on the mag, I just don't know how low yet, but I know it's negatively affecting my sps..."I'm glad I didn't start out with a whole colony." These are the things that come with experience...

<a href=showthread.php?s=&postid=10094431#post10094431 target=_blank>Originally posted</a> by argi
Also forgot to mention it could be an issue with competition between corals. Do you have lots of leather corals in the tank?

I have one yellow fiji leather and a few common LPS, also a couple of monti-caps with the five frags I was telling you guys about. In comparison to some coral tanks mine is bare, but I do stock heavy with fish as I like'm the most. Competition could be a possibility, but
not with other corals..."I don't have enough corals to promote competition among them."