Magnesium/Calcium

[Chris Lakies]

Well - I have been having trouble trying to keep my Calcium above 370 PPM and I think I know why. I picked up a Salifert Magnesium test and did a test last night. It turns out my Mag level is at 240 PPM when it should be 1300-1500! I will pick up some Kent Magnesium Suppliment and try it out.

I have been using Reef Crystals - which I think may be defficient in Mag.

Will I have to add more Calcium to raise it, after my Mag. level is correct?

[Ninong]

Originally posted by Chris Lakies:

It turns out my Mag level is at 240 PPM when it should be 1300-1500!

NSW is approximately 1290 ppm Mg. I don't believe your tankwater is really only 240 ppm Mg. Have it tested again.

[Chris Lakies]

I know I tested it correctly. But I will try again tonight.

[Papa Doug]

Just some info,
Before a reactor, I used ESV magnesium with great success. I found the co2 reactor, keeps the mag at app. 1300ppm.

[Chris Lakies]

Doug,

Were you having problems with Mag levels?

[Barry N.]

I was having touble keeping my mag. up for 1100 when I was using RO/DI water, now I am using RO and mag is up over 1300.

Barry

[Papa Doug]

Not really. It would slowly decline though. I never had to add much to keep it at 1200ppm. My well water contains some magnesium. Depends if I use ro water. Its softened first. Sometimes I use well water just run through a particle filter.

With a co2 reactor, the effluent from my ARM media, always was high in magnesium. I always measure with a Salifert kit.

[Chris Lakies]

Well I tested again yesterday before I added some Seachem Mag. My first reading was correct at 240ppm.

Today my Mag is up to 300 after the addition of the buffer.

I'm going to add the buffer as directed until I get it up a little further.

I get my CO2 bottle tomarrow and will be setting up my calcium reactor.

[Ninong]

Originally posted by Ninong:
I don't believe your tankwater is really only 240 ppm Mg. Have it tested again.



P.S. -- The reason I suggested that you have it tested again is because I do not believe that it is possible to have only 240 ppm Magnesium. ;) As a matter of fact, it is impossible to have both 370 ppm Calcium and 240 ppm Magnesium in the same water sample. If your Calcium is 370 ppm, then your Magnesium is definitely above 1000 ppm and more likely above 1100 ppm. If I had to venture a guess, I would guess that it would be somewhere around 1190 ppm. (P.S. -- I may have overstated things here a little. Let me revise that by saying it is not possible to have both 370 ppm Calcium and 240 ppm Magnesium in a sample of natural saltwater. I am not sure how low you can deplete magnesium in a reeftank but I suspect that you cannot approach 240 ppm. )

[Reefland]

I'm not familiar with Saliferts Magnesium test but does it contain a formula that you are mis-interpeting? For a "normal" reading to be 1300, 240 sounds way off and as Ninong mentioned, maybe not even possible.

Just a thought,
Scott Z.

[Chris Lakies]

It is possible that I am not reading the chart correctly. I will send to this board exactly what it says - maybe you can help.

Thanks

[Ninong]

Chris,

What are the steps involved in performing that test? I couldn't find the instructions online. Perhaps you are overlooking something.

[Reefland]

I emailed Dr. Randy Holmes-Farley and here was his response:

I think it is unlikely that the tank depleted down to 240 ppm from natural levels unless it is a very old tank. OTOH, he could have been using a salt mix that is low in magnesium.

With it that low, adding enough to fix it is a big correction. I'd suggest that he test his salt mix first to verify both the salt mix and the kit, and then either do some big water changes, or get something like ESV's magnesium product and add it.

Scott Z.

[Ninong]

Scott,

I don't know of any commercially available saltmixes that are so low in magnesium that they could account for a reading of only 240 ppm. Here is the magnesium measured in several common commercial salt mixes:

http://www.animalnetwork.com/fish2/a...s/1/photo2.asp

I believe that magnesium depletion in reeftanks is a very slow process and could not possibly account for a reading of 240 ppm. Too many negative effects would have become evident long before such a level had been reached. I don't think it is possible to get your chemistry that far out of balance and still have a reeftank that hasn't crashed. In the 23 reeftank water samples that Dr. Shimek tested, magnesium levels ranged from a low of 1000 ppm to a high of 1500 ppm: http://www.reefkeeping.com/issues/20...ture/index.htm

[Reefland]

I would say, after reading all this information, that there is something wrong with the test kit or the way it is being read. I wish I had one handy so I could help out from that end.

Scott Z.

[Ninong]

Well, I have already sent a private message to Dr. Habib Sekha, the president of Salifert requesting his input.

[Chris Lakies]

Ok, lets say I'm reading the test wrong and my Mag. levels are good.

Why would I not be able to raise my Calcium levels past 370ppm?

I use my Xenia colonies to monitor Iodine levels (they will kind of shrink and not pulse as much)

Alk is aprox. 2.5 meq/L

PH range is aprox. 7.92 night and 8.2 day.

I also dose Kalk for top off.

Water changes with Reef Crystals done once a month at the least 15-20%

I am going to set up a Calcium reactor within the next week.

[Chris Lakies]

By the way - thanks for all the input and help.

Should I not worry about this because I'm setting up the calcium reactor? My clam, sps, softies are fine.

[Ninong]

Originally posted by Chris Lakies
Why would I not be able to raise my Calcium levels past 370ppm?

I use my Xenia colonies to monitor Iodine levels (they will kind of shrink and not pulse as much)

Alk is aprox. 2.5 meq/L

PH range is aprox. 7.92 night and 8.2 day.

I also dose Kalk for top off.

Water changes with Reef Crystals done once a month at the least 15-20%

I am going to set up a Calcium reactor within the next week.

If you want to raise your calcium levels, you have to occasionally dose CaCl in addition to Kalkwasser. Kalkwasser maintains levels, CaCl raises them. Also, you should get your alkalinity up some from your absolute minimum of 2.5 mEq/L. A better level would be 3.5 - 4.3 mEq/L.

I think if you are doing monthly water changes with Reef Crystals, then you do not have 240 ppm Mg in your tankwater. Reef Crystals tested at 1220 ppm Mg in the study done by Atkinson & Bingman.

[Ninong]

I think that the calcium reactor will make it easier for you to maintain your calcium and alkalinity at optimum levels. It might still be necessary for you to add a little CaCl every once in a while but the calcium reactor will make those additions very few and far between if it doesn't eliminate them altogether.