Sucking up the mag

[ryshark]

My tank seems to be sucking up the Magnesium quickly. I have been dosing every single day and still am having a hard time keeping it around 1350. Does this sound normal for a reef tank to eat mag this quickly? I am currently using DD salt mix and Warner Marine Mag for dosing. My BRS 3-part arrives tomorrow.
Just to get an idea here is what I have been testing/dosing my 180-gallon tank. All the test were with Elos.
October 21st- 1350 did not dose
October 25th- 1200, then dosed 105ml of mag
I did dose in between the 25th and 1st, between 90-105ml almost daily
November 1st- 1300, then doesed 90ml of mag
November 2nd- 1250, then doesed 105ml of mag

I thought alk and cal were more of a daily dosing thing, is magnesium typically dosed daily as well in sps/mixed reefs?

[Billybeau1]

Typically, magnesium depletes at a much slower rate than calcium and alkalinity. Usually magnesium only needs supplementing about once a month or so, if at all depending on your salt mix.

Magnesium test kits have a lot of test noise so I would not get excited about 100 ppm either way. Hobby grade magnesium kits just work that way.

[ryshark]

I thought I was dosing mag way too often. Do growing coral use mag? Thanks for the info on the 100ppm either way on the hobby grade kits.

[cccapt]

A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH (http://reefkeeping.com/issues/2006-06/rhf/index.php)
"Corals and coralline algae use calcium and alkalinity almost exclusively to deposit calcium carbonate. Because of this they use a fixed ratio of calcium to alkalinity, which is driven by the ratio of calcium and carbonate in calcium carbonate (1:1). The net consumption is about 18-20 ppm of calcium for each 1 meq/L (2.8 dKH) of alkalinity. The reason the amount of calcium varies is that the incorporation of magnesium in place of calcium varies a bit from species to species."

My understanding is aprox 1 meq/l alk, aprox 18 ppm ca and aprox 2 ppm mag is used in calcification.

[Randy Holmes-Farley]

I agree that you are most likely seeing noise in testing.

It also takes a huge amount of additive to see a boost. In 180 gallons of water, which you bio says you have, it takes 850 mL of the Warner Reefpure Magnesium additive to see a 100 ppm boost. You can use this for such calculations:

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

[DeathWish302]

What's the Mg level in your WC (if you perform those and how often)? I'm changing 1% daily and have to add about 0.15mL/gal per day to maintain my Mg at 1350 with IO.

How old is that Mg test kit and what brand? I've found Salifert a little better than most other hobby grade kits, but Billybeau is the Gawd of Testing...

With a rock solid test kit and the BRS MgCl you should be able to dial in a weekly dose regime in a few weeks. Once you have it down, it doesn't change much unless there is explosive coral growth.

[ryshark]

A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH (http://reefkeeping.com/issues/2006-06/rhf/index.php)
"Corals and coralline algae use calcium and alkalinity almost exclusively to deposit calcium carbonate. Because of this they use a fixed ratio of calcium to alkalinity, which is driven by the ratio of calcium and carbonate in calcium carbonate (1:1). The net consumption is about 18-20 ppm of calcium for each 1 meq/L (2.8 dKH) of alkalinity. The reason the amount of calcium varies is that the incorporation of magnesium in place of calcium varies a bit from species to species."

My understanding is aprox 1 meq/l alk, aprox 18 ppm ca and aprox 2 ppm mag is used in calcification.

Thanks for that, I hope I can get to the point where I use up a 1:1 ratio

[ryshark]

I agree that you are most likely seeing noise in testing.

It also takes a huge amount of additive to see a boost. In 180 gallons of water, which you bio says you have, it takes 850 mL of the Warner Reefpure Magnesium additive to see a 100 ppm boost. You can use this for such calculations:

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

Thanks for that calculator. Which mag supplement on that calculator is closest to the BRS mag? Its too bad there is that much noise in the high end hobby grade mag kits. That just goes to show how bad the cheap ones must be.

[ryshark]

What's the Mg level in your WC (if you perform those and how often)? I'm changing 1% daily and have to add about 0.15mL/gal per day to maintain my Mg at 1350 with IO.

How old is that Mg test kit and what brand? I've found Salifert a little better than most other hobby grade kits, but Billybeau is the Gawd of Testing...

With a rock solid test kit and the BRS MgCl you should be able to dial in a weekly dose regime in a few weeks. Once you have it down, it doesn't change much unless there is explosive coral growth.

The mag level of.my weekly 15-gal WC tested at 1350 on my new Elos test kit. My BRS 3-part arrives today, this will be the first time I try brs 3-part. I have had lots of growth lately after months of not much growth. I sparked the new growth by first buying all new high end test kits and throwing away all my expired cheap kits. Then I started testing everyday and dosing a lot to get parameters in whack. I also bought pinpoint refractometer solution and found out calibrating with rodi is not good. I was much lower than I thought I was,

[Randy Holmes-Farley]

Which mag supplement on that calculator is closest to the BRS mag?

Are you dissolving it in water?

[Darejohn]

use RO water first!

[DeathWish302]

The mag level of.my weekly 15-gal WC tested at 1350 on my new Elos test kit. My BRS 3-part arrives today, this will be the first time I try brs 3-part. I have had lots of growth lately after months of not much growth. I sparked the new growth by first buying all new high end test kits and throwing away all my expired cheap kits. Then I started testing everyday and dosing a lot to get parameters in whack. I also bought pinpoint refractometer solution and found out calibrating with rodi is not good. I was much lower than I thought I was,

BRS and MagFlake are very similar in consistency when mixed as Randy or BRS has for the MgCl & MgSO4*7H2O recipe. I would use 'Randy's 1 & 2 Recipe A & B' if using the below Mg supplement:
http://reefkeeping.com/issues/2006-07/rhf/index.php

Good move on ditching the test kits for some fresh ones while your getting the hang of this additive system. Honestly once you get a feel you won't test nearly as much as in the beginning. I'm usually within 10-20ppm for a guess where I'm at when I do perform a monthly 'feel good' round of testing.

As for the refractometer calibration solution, try this when you need a refill. If you have access to a scale, you can make a liter of dead-on calibration solution for the cost of the soda!
http://reefkeeping.com/issues/2004-06/rhf/index.php

:cool:

Speaking of MAG... How's that fresh bag working out for you Larry? Haven't needed yet, so wondering consistency to your current stock.

[ryshark]

Which mag supplement on that calculator is closest to the BRS mag?

Are you dissolving it in water?

I haven't read the directions yet, but I am pretty sure I will disolve a powder in RODI water.

[Randy Holmes-Farley]

Once you make it into the liquid (8 total cups or so per gallon of fresh water), then use the entry on the calculator for Randy's recipe, as mentioned above.

[cccapt]

Speaking of MAG... How's that fresh bag working out for you Larry? Haven't needed yet, so wondering consistency to your current stock.
Perfect. :) I was down to my last few flakes until you came thru for us.