Saturation Levels of CaCl and MgCl in RO/DI Water

[Todd]

I think Randys recipies are near saturation because it sure takes alot of mixing, and a little heat, to get them fully disolved.

Thanks! That was the info that I was looking for. I am sure it wouldnt have taken me long to figure it out by trial and error, but I figured why bother if someone else had already figured it out.

Originally Posted by littlesilvermax

FWIW calcium get used up at a much higher rate in your tank then magnesium.

What salt are you using, what is the magnesium and calcium level of that salt?

Thanks for the info. I am aware that the uptake levels will be different, and I am planning on using different dosing schedules for CaCl and Mg to address that.

I am using IO salt, the Ca level is usually 380 and the Mg level usually tests around 1100 using a Salfart test kit.

Here is a problem I am having though, perhaps someone will have some insight into: I have tested my wc water and found a Mg level of 1080, I then proceed to add 85g of MgCl and 85g of MgSO4 to bring my Mg levels up. I noticed no precipitate. After letting my heated water change water sit mixing, I tested my Mg levels again, only to find them unchanged and still at 1080.

I tried to do the same thing with my next batch of water change water only to have the same thing happen (levels the second time were 1020 starting, added 56g MgSO4 and 66g MgCl along with 17g CaCl).

Is this a problem with my test kit? Do the test kits work in a way that they will not measure Mg added in this way? Could it have precipitated out and I not noticed? Anything else I am not thinking of?

[littlesilvermax]

Originally Posted by Todd

Thanks for the info. I am aware that the uptake levels will be different, and I am planning on using different dosing schedules for CaCl and Mg to address that.

I am using IO salt, the Ca level is usually 380 and the Mg level usually tests around 1100 using a Salfart test kit.

Here is a problem I am having though, perhaps someone will have some insight into: I have tested my wc water and found a Mg level of 1080, I then proceed to add 85g of MgCl and 85g of MgSO4 to bring my Mg levels up. I noticed no precipitate. After letting my heated water change water sit mixing, I tested my Mg levels again, only to find them unchanged and still at 1080.

I tried to do the same thing with my next batch of water change water only to have the same thing happen (levels the second time were 1020 starting, added 56g MgSO4 and 66g MgCl along with 17g CaCl).

Is this a problem with my test kit? Do the test kits work in a way that they will not measure Mg added in this way? Could it have precipitated out and I not noticed? Anything else I am not thinking of?

I have never noticed any magnesium to prec out when I mix my IO water, and I have mixed A LOT of IO water.

Salifert test kits as of late are not that great.

I would add about 9 times the amount of MgCl vs MgSO4. Otherwise you get too high a sulfate in the water. Not a big deal though.

Try (what I always do) mixing the calcium and magnesium in the water BEFORE you add the salt.

FWIW if you get the IO water up to about 1380 ppm or so, it is unlikely that you will have to dose magnesium to the main tank. Unless you use a lot of kalk.

[tang daddy]

Todd here is the read up I pulled the article from intresting read and a whole different perspective on Mg and really how important it is to our hobby....

http://www.advancedaquarist.com/issues/oct2003/chem.htm

[Todd]

Originally Posted by littlesilvermax

Salifert test kits as of late are not that great.

I would add about 9 times the amount of MgCl vs MgSO4. Otherwise you get too high a sulfate in the water. Not a big deal though.

Try (what I always do) mixing the calcium and magnesium in the water BEFORE you add the salt.

FWIW if you get the IO water up to about 1380 ppm or so, it is unlikely that you will have to dose magnesium to the main tank. Unless you use a lot of kalk.

Great tips, particularly mixing the Mg before adding the salt. I will try that next time. Also good to know about the Sulfate accumulation, I could not find the reasoning behind the ratio's, but that makes sense.

I will have begin a dosing schedule to bring my Mg levels up in my display, while still bringing my water change water up before doing changes. Once I get my levels upto 'normal', then I will see if I can move away from dosing Mg. I am not using any Kalk, I will just be adding Calcium, Magnesium and Alkalinity via dosing pumps.

I guess I should try another brand of test kit. Any suggestions?

[littlesilvermax]

Originally Posted by Todd

Great tips, particularly mixing the Mg before adding the salt. I will try that next time. Also good to know about the Sulfate accumulation, I could not find the reasoning behind the ratio's, but that makes sense.

I will have begin a dosing schedule to bring my Mg levels up in my display, while still bringing my water change water up before doing changes. Once I get my levels upto 'normal', then I will see if I can move away from dosing Mg. I am not using any Kalk, I will just be adding Calcium, Magnesium and Alkalinity via dosing pumps.

I guess I should try another brand of test kit. Any suggestions?

Try the Elos test kits. So far they seem to work well for me.

Once you get your display tank up to about 1380-1460 ppm (what I recommend) you will likely not have to dose the tank at all. Just make sure your newly made up water for water changes has the above ppm of magnesium and you should be fine. The only time I could foresee you having a problem is if you had heavy kalk use.

Randy at RC (one of the resident chemists) has published a few articles about magnesium. I think his latest tests reveal that a 9:1 ratio of MgCl : MgSO4 was optimal. It is not at all critical (and actually depends a lot on the sulfate levels in your salt) but may as well get it close if you can.

You are right in magnesium being a very important key in keeping your levels up. I think cal, alk, and mag are the big three, too many times people don't mention magnesium. That is wrong! W/o the right magnesium levels you will never be able to attain NSW amounts of alk and calcium. That is why I got into bulk magnesium sales a few years ago.

[Todd]

Originally Posted by littlesilvermax

Try the Elos test kits. So far they seem to work well for me.

Once you get your display tank up to about 1380-1460 ppm (what I recommend) you will likely not have to dose the tank at all. Just make sure your newly made up water for water changes has the above ppm of magnesium and you should be fine. The only time I could foresee you having a problem is if you had heavy kalk use.

Randy at RC (one of the resident chemists) has published a few articles about magnesium. I think his latest tests reveal that a 9:1 ratio of MgCl : MgSO4 was optimal. It is not at all critical (and actually depends a lot on the sulfate levels in your salt) but may as well get it close if you can.

You are right in magnesium being a very important key in keeping your levels up. I think cal, alk, and mag are the big three, too many times people don't mention magnesium. That is wrong! W/o the right magnesium levels you will never be able to attain NSW amounts of alk and calcium. That is why I got into bulk magnesium sales a few years ago.

Thanks again for the info. I am looking forward to getting my tank back into that range! I will use the 9:1 ratio, as I really have no reason not too.

Reading over some of Randy's articles has shown me just how important Mag is, not just for the biological functions of corals but also the abiotic functions of preventing precipitation (thanks tang daddy).

I think that I will get a Elos test kit, as I have lost confidence in my Salfart kit.