Magnesium

[CarlaW]

Ok, just did my weekly water tests and here's the story.
alk-3.14
Ca-420
Mg-1200
The Mg is a little low compared to natural sea water levels, but it is still about 3 times what the Ca level is. Do I dose a little Mg to get the level to 1300, or do I ride the tide and let it go?
I am using Oceanic salt, have been since July.
Let me know if you need any more test results, I can definitly accomodate.
Thanx in advance,

 

[WaterDogs]

Hi charlie,

People that have helped me always said 1250 was ideal. According Salifert test kit instructions they say don't go over 1500 for a maximum. At 1200 I personally would add and bring it up to 1250 then check it again in a week and see how much it dropped.

Dwaine

 

[CarlaW]

Thanx WaterDogs, I had a hunch that was what someone was gonna tell me, let's see if anybody else has an opinion.

 

[DonW]

Mg falls real slow, but I'd do a WC to bring it back up since your using Oceanic. You just dont want to have calcium problems down the road. Once it gets to low its a real pain to get it back up.

Don

 

[CarlaW]

I have never measured the wc water for Mg. Maybe I'll go do that now since I just happen to have some handy!! Keep those opinions coming, they are always helpful.

 

[CarlaW]

Well, I came up with a reading of 1470. I do a 20 gallon WC every week. Does anybody think that this will be enuf to raise my Mg without having to dose? I could own stock in Seachem if I followed their dosing calculations!!!!!!

 

[DonW]

Charlie

It will bring it up. Save your money.

Don

 

[CarlaW]

Thanx Don, I think I'll go with that. How soon after a change would you recommend testing, 1hr., 2hr. ???

 

[WaterDogs]

Well, I came up with a reading of 1470. I do a 20 gallon WC every week. Does anybody think that this will be enuf to raise my Mg without having to dose? I could own stock in Seachem if I followed their dosing calculations!!!!!!

A 20 gallon WC isn't going to bring 475 gallons of water up to 1250.

Dwaine

 

[CarlaW]

That is a good point, but right now, it comes down to a point of affordabilty. I'm kind of stuck between a rock and a hard spot. According to Seachems formula, I need to dose 150 teaspoons of their additive to get it up to 1250. There aren't 150 teaspoons in the bottle that I have!!!!!!!!!!!! Maybe a larger WC???

 

[WaterDogs]

I'd say a balance of larger WC and the Mg additive. I only have 75 gallons to care for so I never thought of having to use more than the whole bottle of an additive!

 

[MikeS]

Curious, what SG do you keep you main tank at?

MikeS

 

[Boomer]

I need to dose 150 teaspoons of their additive to get it up to 1250

Or 3.3 pounds of Calcium Chloride

Go here

http://www.andy-hipkiss.co.uk/

Click on Physical Environment----->Chemistry---> Mag Sups

I would take WaterDogs advice but you are not that low.


Reading

Magnesium in Reef Aquaria
http://www.advancedaquarist.com/issues/oct2003/chem.htm

Magnesium: Calcium's little sister
http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=2345

Curious, what SG do you keep you main tank at?

Me too Mike &

1. Who's Sg meter/refract, floater, swing arm

2. What temp is the tank

3. What temp is the Sg calibrated to

4. If it is a refract is it corrected for seawater's "15" units negitive error

 

[CarlaW]

Specific gravity is at 1.024 with a refractometer.
Temp in tank is 78-81.
Calibrated to 78.

Boomer, thanx for the reading, assignment, a guy can always get used to Randy Holmes Farley @ 6 AM on a Saturday morning. Whew, I think I need more coffee .
RE., WaterDogs advice, instead of a larger change, would a few 20 gallon changes in a week along with a one time supplementation,(all I've got), help to get me to 1250, at a bare minimum?

 

[DonW]

WC are easy and cheap. You dont need to do it all in one shot. Just at a faster rate than your using it. Your not that far off.

Don

 

[WaterDogs]

Hi Charlie,

A 10% water change a week would be 47.5 or 50 gallons in round numbers. I would take out 50 gallons then put in the new 50g then add the whole bottle of Mg and you may be very close and able to maintain with just WC after that especially with Oceanic's high Mg level. There is a point where salt will cost just as much as the additive and sweat .

You could change 100gallons a week if you wanted just don't shock the system whatever you decide to do. I know an increase from 1200 to 1250 in one shot is safe.

How much will Epsom salts cost as the site Boomer recommended http://www.andy-hipkiss.co.uk/ says it can be used and I think RHF said that also.

Let us know what you decide upon?

Dwaine

 

[Boomer]

charlie

Your SG it to low, what is part of your problem

1.024 -15 units = a real SG of 1.024 - .0015 = 1.0225 = 30 ppt

You are way to low on your salinity and need to get to 35 ppt. Your refract needs to read;

1.028, which with the error correction = 1.028 - .0015 = 1.0265 corrected = 35ppt NSW. Raising your salinity up to NSW will give you a 15 % increase in Mg but that Ca will also increase 15 %. Of course that would be if you were starting with all new water. I like so far WD suggestion and see what you get


With a salinity that low is a major reason your Mg is so low. Part of your problem is going to be Oceanic salt, if that is what you are using, has it usually has a very high Ca. I did not know the Mg was also high.



WD

Are you sure about that high Mg or are you mistaking it for high Ca ?

 

[CarlaW]

How would you go about raising the salinity? Make my next batch of change water @ 1.030?

 

[WaterDogs]

Boomer asked:
WD

Are you sure about that high Mg or are you mistaking it for high Ca ?


WD:
Not mistaking it for CA. That is mostly what I have read/heard; when I was using Oceanic salt at 1.026 on a refrac my Mg was always close to or over 1500, but my reef is lightly stocked so usage is low.

Maybe someone here could mix some batches of Oceanic and test Mg for us?

Dwaine

 

[CarlaW]

My batch of oceanic tested @ 1470 as I stated earlier