Why's my magnesium so low?

[Masterderrull]

Hey everybody, I'm looking for some advise on mag. levels in my aquarium. I noticed about two months ago that alot of my coraline algae was turning brownish-green, and that the thick coraline was dissapearing. Since then I've got some salifert test kits and tested for magnesium, calcium, and alk and all - in my opinion - are very low. My Ph is at 8.3, alk at 1.1, mag at 600ppm, and cal. at 225. I had understood that mag kind of controls the rest of them because it alows the others to dissolve properly, but maybe i'm wrong. Is there something i'm missing? So far i've added about 200g of mag. as well as plenty of cal. and alk. I have seen some increase in the past weeks, but wanted to get everybodys opinion on the matter. Thanks for any suggestions you have.

 

[Tswifty]

Honestly... all your numbers are VERY low (1.1 meg/l converts to roughly 3 dKH). Here is a chart which shows the recommended params for a Reef Aquarium:

Reef Aquarium Water Parameters

What type of tank are you running, and how heavily stocked are you coral wise? Do you add anything daily, weekly, etc... to maintain your levels?

Are you sure it isn't a testing error? Make sure you are reading the numbers properly... you use the amount that is left in the syringe at the end of the test, then get the corresponding reading from the chart. (Not to sound condescending or anything, I just had a friend do this and he was using the amount that he squirted into the vial to get his number, rather than what was left in the syringe at the end of the test).

Assuming you are performing regular water changes, that is a VERY low number. The same with your Ca & Alk. What salt are you using?

Also, are you dosing blind, or using the Reef Chemistry Calculator to determine how much to add? You could get some nasty side effects by just guessing how much to dose, as well as potentially having a precipitation event if you overdose which will basically nullify everything you added.

However, with numbers that low, a water change would probably be more useful than trying to dose from that point.




Sorry for the shotgun blast of questions/info.

 

[Aqua-World PITT]

Yeah I agree the levels are pretty low. Good levels are:
(These levels are arguable)

Mixed Tank (SPS, Softies, LPS)
Ca-375
KH-8.5
Mg-1200
pH-8.2
Sal-1.023-1.024

SPS only
Ca-400
KH-10
Mg-1200
pH-8.2
Sal-1.023-1.024

Softies
Ca-350
KH-7
Mg-1100
pH-8.2
Sal-1.023-1.024

 

[cloakerpoked]

You are correct about the magnesium also. What happens is the magnesium allows the calcium and alk. ions to remain suspended in the water column longer. Without the magnesium, the calcium and alk precipitate faster (usually on pumps and stuff) and fall out of the water column, basically becoming useless. Because of that, you could even be taking measures to keep your alk and calcium at good levels, but because of the low magnesium level, if falls out of suspension before it can do any good. I'd take Tswifty up on his advice and do a large water change with salt that will replace all those elements at once rather than dosing it to get there.

 

[Masterderrull]

thanks guys. I am using instant ocean reef crystals, and have a 55 gal lightly stocked reef. I do water changes about every two weeks (my filtration unit isn't what i wish it was), but maybe I'll try doing a few more than normal to get things back up to par. And yes tswifty i was reading the numbers right even though i did have to read them several times before I fully understood. I didn't think you were being condisending. Thanks again and if i have any more trouble I'll ask.

 

[Tswifty]

If you're lightly stocked I am surprised your levels are that low? 2 weeks isn't THAT long to go if your demand isn't that high.

When you make a batch of new water change water... I would test that for the Ca, Alk & Mag levels, and see what you get.

Do you dose any type of supplement daily or week to maintain your Ca or Alk levels? If your levels on the fresh SW come out normal, then you will probably need to begin a dosing regiment of some sort. ESV B-Ionic 2-Part is an easy product to use.

 

[rickyfins]

RC by Instant Ocean tends to be low in Mag(EDIT: about 1000), so if it is used up regularly you will have constant low numbers! Red Sea Coral Pro tends to have higher Mag, but water changes alone will take forever to raise your Mag. Either get a very large quantity of liquid Mag(+1gal) or do Randy's 2 Part Mag dosing.

I would dose Mag after you get alk and cal close to in line! If not your alk and cal can bottom out and cause more problems. Try working on 1 of them at a time so you are not fighting each one. I would start with Alk, then move to Cal, finally Mag.

Here is a link to the Chemistry Calculator:

http://home.comcast.net/~jdieck1/chem_calc3.html

 

[Tswifty]

Actually Reef Crystals isn't much lower than Red Sea. However, a while ago they did have a batch of bad buckets get out with low mag. I agree that Red Sea is probably more consistently in line with the values below than Reef Crystals though.

Dosing when your Mag is/was as low as the OP's is a waste of money. A large water change would bring it up much faster for a lot less... or at least get you to a better point to begin dosing from.

<table align=center><tr><td valign=top></td><td valign=top><p align=center style='text-align:center'>Calcium &nbsp&nbsp</p></td><td valign=top><p align=center style='text-align:center'>Alkalinity&nbsp &nbsp</p></td><td valign=top><p align=center style='text-align:center'>Magnesium</p></td></tr> <tr ><td valign=top ><p>Aquatic Gardens</p></td><td valign=top ><p>&nbsp&nbsp 430</p></td><td valign=top ><p>&nbsp&nbsp 8</p></td><td valign=top ><p>&nbsp&nbsp 1240</p></td></tr> <tr ><td valign=top ><p >CoraLife</p></td><td valign=top ><p>&nbsp&nbsp 560</p></td><td valign=top sp 9><p>&nbsp&nbsp 9</p></td><td valign=top ><p>&nbsp&nbsp 1380</p></td></tr> <tr><td valign=top ><p>Crystal Sea Marinemix&nbsp &nbsp</p></td><td valign=top ><p>&nbsp&nbsp 340</p></td><td valign=top ><p >&nbsp&nbsp 9</p></td><td valign=top ><p>&nbsp&nbsp 1050</p></td></tr> <tr><td valign=top ><p>Crystal Sea Marinemix Bio-Assay&nbsp &nbsp</p></td><td valign=top ><p>&nbsp&nbsp 340</p></td><td valign=top ><p >&nbsp&nbsp 9</p></td><td valign=top ><p>&nbsp&nbsp 1050</p></td></tr><tr><td valign=top ><p>D-D H2Ocean&nbsp &nbsp</p></td><td valign=top ><p>&nbsp&nbsp 450</p></td><td valign=top ><p >&nbsp&nbsp 10</p></td><td valign=top ><p>&nbsp&nbsp 1380</p></td></tr> <tr><td valign=top ><p>Instant Ocean&nbsp &nbsp</p></td><td valign=top ><p>&nbsp&nbsp 350</p></td><td valign=top ><p >&nbsp&nbsp 12</p></td><td valign=top ><p>&nbsp&nbsp 1070</p></td></tr> <tr><td valign=top ><p>Kent&nbsp &nbsp</p></td><td valign=top ><p>&nbsp&nbsp 540</p></td><td valign=top ><p >&nbsp&nbsp 11</p></td><td valign=top ><p>&nbsp&nbsp 1200</p></td></tr> <tr ><td valign=top ><p>Marine Environment</p></td><td valign=top ><p>&nbsp&nbsp 480</p></td><td valign=top ><p>&nbsp&nbsp 7.5</p></td><td valign=top ><p>&nbsp&nbsp 1450</p></td></tr> <tr ><td valign=top ><p>Oceanic</p></td><td valign=top ><p>&nbsp&nbsp 580</p></td><td valign=top ><p>&nbsp&nbsp 8.5 </p></td><td valign=top ><p>&nbsp&nbsp 1650</p></td></tr> <tr ><td valign=top ><p>OceanPure</p></td><td valign=top ><p>&nbsp&nbsp 510</p></td><td valign=top ><p>&nbsp&nbsp 10</p></td><td valign=top ><p>&nbsp&nbsp 1320</p></td></tr> <tr ><td valign=top ><p>Red Sea</p></td><td valign=top ><p>&nbsp&nbsp 400</p></td><td valign=top ><p>&nbsp&nbsp 8</p></td><td valign=top ><p>&nbsp&nbsp 1300</p></td></tr> <tr ><td valign=top ><p>Red Sea Coral Pro</p></td><td valign=top ><p>&nbsp&nbsp 490</p></td><td valign=top ><p>&nbsp&nbsp 7</p></td><td valign=top ><p>&nbsp&nbsp 1300</p></td></tr> <tr ><td valign=top ><p>Reef Crystals</p></td><td valign=top ><p>&nbsp&nbsp 420</p></td><td valign=top ><p>&nbsp&nbsp 12</p></td><td valign=top ><p>&nbsp&nbsp 1260</p></td></tr> <tr ><td valign=top ><p>Reefer's Best</p></td><td valign=top ><p>&nbsp&nbsp 420</p></td><td valign=top ><p>&nbsp&nbsp 11</p></td><td valign=top ><p>&nbsp&nbsp 1200</p></td></tr> <tr ><td valign=top ><p>SeaChem Marine Salt</p></td><td valign=top ><p>&nbsp&nbsp 500</p></td><td valign=top ><p>&nbsp&nbsp 10</p></td><td valign=top ><p>&nbsp&nbsp 1400</p></td></tr> <tr ><td valign=top ><p>SeaChem Reef Salt</p></td><td valign=top ><p>&nbsp&nbsp 540</p></td><td valign=top ><p>&nbsp&nbsp 10</p></td><td valign=top ><p>&nbsp&nbsp 1450</p></td></tr> <tr ><td valign=top ><p>Tropic Marin</p></td><td valign=top ><p>&nbsp&nbsp 375</p></td><td valign=top ><p>&nbsp&nbsp 10</p></td><td valign=top ><p>&nbsp&nbsp 1230</p></td></tr> <tr ><td valign=top ><p>Tropic Marin Pro Reef</p></td><td valign=top ><p>&nbsp&nbsp 450</p></td><td valign=top ><p>&nbsp&nbsp 8.5</p></td><td valign=top ><p>&nbsp&nbsp 1380</p></td></tr><tr ><td valign=top ><p>Tunze Reef Salt</p></td><td valign=top ><p>&nbsp&nbsp 420</p></td><td valign=top ><p>&nbsp&nbsp 9.5</p></td><td valign=top ><p>&nbsp&nbsp 1350</p></td></tr> </table>