Magnesium extremely low...

[Alex1524]

Hey guys. So I measured my magnesium today and said it was at 750 (Checked twice. Brand new Elos) My calcium is at 340 and dkh is at 12. Ammonia, nitrate, and nitrate are at 0 and PH at 8.3. I have been doing my biweekly water changes and don't understand how my magnesium is so low. It makes me think the water I get from the LFS is not legit. What do you guys suggest I do because clearly water changes isn't working? I'm thinking about buying my own bucket of salt and making my own water.

 

[DrBegalke]

I would verify with a different test kit, but if it is that low, I would use a magnesium supplement to bring it up slowly, 100 ppm per day.

I would also test your freshly made saltwater to see what that mag is.

 

[bertoni]

I don't believe the number yet, and I agree with trying another kit. You could try measuring some freshly-mixed saltwater, too, as a sort of sanity test.

 

[merkurmaniac]

Your numbers are almost exactly what I was facing. I tried all kinds of Mg additions and it barely budged. The calculators said that I would need to add two bottles of Tech M.!!

I'd add some mag everytime I would walk by and it still did little to change the situation.

I finally ordered a new Mg test (which read the same as the old one, btw) and then a jug of Mg supplement. Before I added it, I read about the driveway ice melting mg chloride. I tried dosing with a small amout of epson salt, but I was concerned about sulfates buildup. I ordered some safestep driveway ice melter online, from Ace Hardware. they shipped it free to my store. I calced that I needed to add about 400 grams of it. I made up a solution and over 4 days or so, I added it. It did boost my Mg up to about 1400. It had started out months before around 700.

I need to test tonight and see if the Mg addition from a week ago is holding, or if its being consumed at a fast rate somehow.

 

[Randy Holmes-Farley]

Hey guys. So I measured my magnesium today and said it was at 750 (Checked twice. Brand new Elos) My calcium is at 340 and dkh is at 12. Ammonia, nitrate, and nitrate are at 0 and PH at 8.3. I have been doing my biweekly water changes and don't understand how my magnesium is so low. It makes me think the water I get from the LFS is not legit. What do you guys suggest I do because clearly water changes isn't working? I'm thinking about buying my own bucket of salt and making my own water.

I agree that it is almost certainly test error, with a slight chance of a very bad batch of salt mix or in homogeneity if you made up than than a full bag/ bucket.

Don't just raise the magnesium.

 

[Reef264]

I am leaning on the test kit, Wouldn't the Alk and Calcium Precipitate out of the system with Magnesium levels that low?You would would have different Results for the Alk and Calcium would you?Lower Results I mean?

 

[Randy Holmes-Farley]

Probably would, yes, although I not sure how fast the precipitation would be. I've never heard of an actual case of magnesium being that low.

Also, are you sure you are reading the kit right? Some folks read some kits backwards, and look at the amount remaining in the syringe rather than the amount dispensed. Using a full syringe means a lot of magnesium in most kits.

 

[Alex1524]

Randy! Just the man I was looking for lol So the test kit I have is the Elos Magnesium kit. I tried it twice with the same result last night. I took it to my lfs and asked them to test it with my kit and he got 550 instead of 750. At this point I'm super confused. What do you think I should do? Buy another mag test kit? And test again? My lfs commended getting the brightwell magnesion. Instructions says dose 10ml per 20 gallons so I did half the dose. I just don't understand what's going on :-( Everyone I talk to tells me something different. But now with my test being 750 and the fish store getting 550 before I dose anymore I need to get an accurate mag level!

 

[Randy Holmes-Farley]

I notice now that this is LFS water. Yes, I'd try a big name mix. Maybe the LFS is making it themselves and not doing a good job.

 

[merkurmaniac]

Not to confuse the issue, but I'll chime in again with my experience. I just tested my "big three." My Mg consumed 1.02 ml of titrant meaning that per my seachem test kit, my Mg level has dropped from about 1400 to a little over 1250 (1.0 ml titrant) in about 1 week. I only have about 50 gallons in my system, but drop represents about 200 mg of Mg, IIRC it took 197 grams to raise Mg by about 100 pts. SO... something is using up or absorbing magnesium at a real fast rate.

My aquarium used to test unbelievably low for magnesium, and it was tuff to keep the Ca up when it was in that condition. My Ca just tested as .82 titrant consumed, so a little over 400. dKh = 11. I am planning on dosing 200 mg of Mg until it begins to hold steady. I mix my own salt and use my own RODI water. SG = 1.026.

I beleive the OP and his mg test kits. I used the ELOS test kit where you titrate twice and subtract a from b. I figured it was bad and bought a seachem test kit. It has little cotton balls that strain the precipitate before you do a final titration on the strained soln. It had a reference soln and it tested right on. My earliest test with it was in the low 800's, IIRC.

I have a clam, some SPS, and a bunch of LPS. Dunno what would really want the Mg, but my system was always crazy low in it.

Here is my post from almost exactly 2 years ago:
==========================
Registered Member


Join Date: Dec 2009
Location: Sugar Land TX, a suburb of Houston.
Posts: 143 I have had low calcium readings for a while nad had been dosing ca and alk. Occasionnaly, I have dosed MG as well, but I only did the MG test yesterday for the first time, since its a little more complicated than the others.

For the MG test, ELO is the brand btw, for part A I got 16 drops. For part B, I got 4 drops. So, 16-4 = 12 *50 = 600 !

That seems quite low. Very, very low, in fact. Is this possible ? For my 35 gallon, the calcualtor says that I would need about 2 bottles of MG. I have Kent brand MG, btw.

I am going to double check the MG Test today. Perhaps my test kit is hosed ? Can fish stores stypically test for MG ?

Thanks,
Richard
=============================================

I battled it for a long time and only recently started massive dosings of dry magnesium chloride and that finally elevated it.

 

[Alex1524]

Thanks for the input merk. Sounds like the same exact thing I'm going through. What exactly are you dosing with now? And how much and how often?

 

[Alex1524]

As far as corals I have an elegance coral, torch, frogspawn, 2 zoa frags, montipora capricornis frag, xenia frag, ricordia frag, 1 mushroom frag, and a few branches of montipora digitatas.

Here is a link to pics...

http://reefcentral.com/forums/showthread.php?t=2086121&page=3&highlight=edge+57+build

 

[bertoni]

The magnesium reading might be correct, but that's unlikely. Most people with readings that low tend to have measurement problems. Sometimes, though, people do have problems with batches of salt.

The calcium and alkalinity levels are a bit odd, but are consistent with the use of pH buffers (which all add alkalinity) or some similar products.

 

[Randy Holmes-Farley]

Not to confuse the issue, but I'll chime in again with my experience. I just tested my "big three." My Mg consumed 1.02 ml of titrant meaning that per my seachem test kit, my Mg level has dropped from about 1400 to a little over 1250 (1.0 ml titrant) in about 1 week. I only have about 50 gallons in my system, but drop represents about 200 mg of Mg, IIRC it took 197 grams to raise Mg by about 100 pts. SO... something is using up or absorbing magnesium at a real fast rate.

.

IMO, that cannot be "in tank" consumption. There is just no sink for that much magnesium. For that much to be deposited by deposition of magnesium in calcium carbonate (the only real sink for magnesium), you'd need to be looking at calcium dropping at least ten times that amount, or 1500 ppm in a week. That's just crazy talk.

If real, it must be from water changes with a low magnesium mix.

But I bet it is testing error. Folks have way too much confidence in most hobby test kits.

FWIW, I presume your 1.02 mL is a typo and you mean 1.2 mL?

 

[merkurmaniac]

Here is a link to my recent post about what I have been dosing:

http://www.reefcentral.com/forums/showthread.php?t=2122427
I had mainly used some Kent products after I had bought a dosing pump. I used some stuff called Kent Nano A & B, since my tank was bordering on a nano anyways.

I made up a spreadsheet to handle all my unit conversions and made up some a homebrew version of the Kent Nano cacium portion. Its made from a combination of dry calcuim, liquid magnesium, strontium, Irom, and potassium. I dont test for the last three but instead assumed that their ratio was somehow proper, so I have maintained it. Only recently did I get agressive in fixing my magnesium issue. I first used soe epsom salts, but then chickened out and ordered some liquid Magnesium supplement, but ended up buying some dry mag (sure step ice melter) and used that instead.

I don't go thru my salt stash very quickly, since my tank is smallish. For the first year or so, I was on the first big bucket that I had bought. I ended up ordering another brand of salt, don't recall the name, and I used it up with no big change in Mg. I am on my third brand and I have done a few water changes with it, and there had been no dramatic turnaround in my mag deficiency. I expect that I'll saturate the Mg requirement (wherever it is going) and then I can stop activly dosing Mg. ???

 

[merkurmaniac]

I am having to dose my tank with about 100 grams of dry magnesium chloride hexahydrate. It drops about 100 points (don't recall the exact units of the test kit) each two weeks. It takes 197 gr to raise it 100 points.

So... where is all the mag going ? Any ideas ?

btw, I am dosing the ca and alk at a really stable rate now. They are the homemade mixes detailed in my other post. CA=400-450 and dKh=10.5

 

[pscott99]

I am dosing Mg also. 5 tbsp per day and some in RODI topoff. I started at 1050 now after a couple weeks over 1200. My water changes do not help because the Mg is too low in the salt (IO Reef). It has to be your test kit. Mix up a little test batch outside the tank or have someone else test it. You are quickly going to get into trouble over 1700. Randy knows :worried:

 

[Randy Holmes-Farley]

I am having to dose my tank with about 100 grams of dry magnesium chloride hexahydrate. It drops about 100 points (don't recall the exact units of the test kit) each two weeks. 5

I'm not convinced that is accurate. It sounds like testing error to me.

To drop 7 ppm magnesium each day (100 ppm in 2 weeks), you need to consume something like 70 ppm calcium each day, and probably close to 10 dKH of alkalinity each day. That doesn't happen.

 

[merkurmaniac]

I use a homemade stirring device using a teflon or plastic coated stirring rod that's about 1/4" long. It uses a computer case fan with a neodyum amgnet glued to it. That spins in the solution while I titrate. The tests end up quite repeatable. The first thing that I did when I got my new test kit was to test using the reference solution and it was dead on. Because the solution is constantly mixing, and I titrate slowly near the endpoint, the color change takes place very quickly, as in precisely, not a blurred process via poorly mixed solutions.

If it was a testing error, where do the most common misteps take place ?

 

[Randy Holmes-Farley]

Testing errors?

Some folks misread the instructions (especially reading syringe levels backwards), leave out steps, use the wrong volumes, loose count of drops, use the wrong drip tip, fill the entire syringe including the tip volume, use a kit which is mismanufactured or inherently inaccurate, and many more.

Have you used that kit and method on new salt water to see what you get? Salt mixes can also become inhomogeneous during shipping, with magnesium, for example, settling to the bottom (or top) of a bucket.