DIY MG when using Kalk for Ca/Alk

[IPT]

I manage my Ca/Alk dosing Kalk, and do a 10% WC with IO weekly (or biweekly). I rarely test MG but just did and it is super low....like below 700. I now realize that unlike some of the other 2 part methods Kalk does about nothing for MG and apparently IO is low in it to begin with.

So, I am going dose MG and read a few threads including this one from Randy (https://web.archive.org/web/20170328124558/http://reefkeeping.com/issues/2006-07/rhf/index.php). I plan on using recipe 3 with Mag Flake (some pure DeadSea Mag flake off Amazon) and pure Espom salt. However, I have seen it recommended in a ratio of 10 : 1 (Magflake to Epsom) but also at 7.25 : .75.

The ratio is close, but one favors the Epsom a tad more. This will be used regularly with Kalk so is one ratio better than the other for long term use?

 

[ReefingDreams]

Verify that magnesium number with a different test kit. I really have a feeling that's not right.

 

[IPT]

Verify that magnesium number with a different test kit. I really have a feeling that's not right.

Good point, I do have another brand Kit so I will do that.

 

[ReefingDreams]

Good point, I do have another brand Kit so I will do that.

From ATI: "Proper magnesium levels prevent precipitation of calcium carbonate, which is critical to maintaining the proper levels of calcium and alkalinity."

I know there have been a lot of folks who have been unable to maintain alk/cal when they have low magnesium.

How much kalk are you dosing a day? What size system?

 

[IPT]

From ATI: "Proper magnesium levels prevent precipitation of calcium carbonate, which is critical to maintaining the proper levels of calcium and alkalinity."

I know there have been a lot of folks who have been unable to maintain alk/cal when they have low magnesium.

How much kalk are you dosing a day? What size system?

In the past I have had issues with Precipitation (different tank) but not currently. The tank is a standard 120Gal with a 40gal sump about half full. It's mostly stocked with small frags at the moment and a few LPS with anywhere from 5 to probably 8 heads. Some of the SPS have taken off lately so I am slowly raising how much KALK I dose to maintain an Alk of around 8.4 (HANNA tested). Generally speaking I am not having an issue maintaining Alk in the mid to low 8's. It's been stable there for a few months though as noted I am recently having to increase the dosing - but there is associated SPS growth that explains it. I also added a 3inch T Maxima. CA was 450 today tested with a Salifert.

If you trust the calibration of my LiterMeter I am dosing roughly 2.55 L/day of UN-saturated KALK solution (3 TBSP Kalk to 7 Gal RO/DI water). I usually add about 7 gallons (to a 12 gallon tote) roughly every 2-3 weeks give or take a few days. I am not using a fully saturated solution because I wanted it to dose more often and higher volume to make my ATO have to do very little work. I know as growth occurs I'll have to up the saturation.

For sure I need to redo the MG test for accuracy. Still, I am sure I should be dosing some MG if I am only using KALK dosing and doing small WC's every 1-2 weeks. I don't see how such small WC's alone could maintain MG.

 

[gbroadbridge]

I manage my Ca/Alk dosing Kalk, and do a 10% WC with IO weekly (or biweekly). I rarely test MG but just did and it is super low....like below 700. I now realize that unlike some of the other 2 part methods Kalk does about nothing for MG and apparently IO is low in it to begin with.

So, I am going dose MG and read a few threads including this one from Randy (https://web.archive.org/web/20170328124558/http://reefkeeping.com/issues/2006-07/rhf/index.php). I plan on using recipe 3 with Mag Flake (some pure DeadSea Mag flake off Amazon) and pure Espom salt. However, I have seen it recommended in a ratio of 10 : 1 (Magflake to Epsom) but also at 7.25 : .75.

The ratio is close, but one favors the Epsom a tad more. This will be used regularly with Kalk so is one ratio better than the other for long term use?

Your Magnesium test is incorrect.

Perform a test with a different test kit.

 

[Randy Holmes-Farley Verified Community Expert]

I manage my Ca/Alk dosing Kalk, and do a 10% WC with IO weekly (or biweekly). I rarely test MG but just did and it is super low....like below 700.

Definitely not accurate. Time for RMM.

Just say NO to magnesium testing: RMM is born

OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...

www.reef2reef.com

 

[Randy Holmes-Farley Verified Community Expert]

. Still, I am sure I should be dosing some MG if I am only using KALK dosing and doing small WC's every 1-2 weeks. I don't see how such small WC's alone could maintain MG.

Yes, there's a fixed amount to add to avoid the problems of testing:

Rmm method and Limewater

Hello, I’m wondering how much magnesium chloride/sulfate to add to my tank if I dose 10 gallons of limewater a week. I understand that I need 5-10% magnesium as I do calcium, so how does that calculate out when using limewater? Assume limewater is fully saturated. Thanks!

www.reef2reef.com

 

[IPT]

Yes, there's a fixed amount to add to avoid the problems of testing:

Rmm method and Limewater

Hello, I’m wondering how much magnesium chloride/sulfate to add to my tank if I dose 10 gallons of limewater a week. I understand that I need 5-10% magnesium as I do calcium, so how does that calculate out when using limewater? Assume limewater is fully saturated. Thanks!

www.reef2reef.com

Thanks for the link Randy.

Yup, testing error. I did the test again today with 2 different test kits and got 1360 and 1380. After doing this for as long as I had you would think I would know not to freak out at such an outlying number!

So that said, what is the "target number" these days for Mg in a SPS tank? Might be the article but I haven't had time to get to it yet.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the link Randy.

Yup, testing error. I did the test again today with 2 different test kits and got 1360 and 1380. After doing this for as long as I had you would think I would know not to freak out at such an outlying number!

So that said, what is the "target number" these days for Mg in a SPS tank? Might be the article but I haven't had time to get to it yet.

I think 1300-1350 ppm Mg is a good target, but many folks have their own preferences.

 

[IPT]

This thread provided some good numbers on the topic as well.

RRM method & Limewater

I just read the article on how to use the RRM to dose 5 -10% of magnesium of the calcium dose. So I have an avast marine K2 reactor and only use limewater to top off the evaporated water in my tank. I was unsuccessful on trying to search online on the dosage. So im asking here on your...

www.reef2reef.com