Dosing Magnesium

Randy Holmes-Farley · Aug 23, 2017

CodyRVA said:
Why is this?

Magnesium is precipitated (e.g., into coral skeletons or abiotic precipitates) at a very rough rate of about 1.5 ppm magnesium for each 17.5 ppm calcium and 2.8 dKH of alkalinity.

So to lose 150 ppm magnesium this way in 3 days means you would have also lost 1,750 ppm of calcium and 280 dKH of alkalinity.

Seems unlikely,

I show the math in a reef question of the day:

https://www.reef2reef.com/threads/r...fication-and-the-big-three-parameters.321163/

PAXpress · Aug 23, 2017

Maybe look at your test kit. My salifert kit was giving me issues and I've been using the red sea kit since and havent had issues.

Mike Yaniz · Aug 23, 2017

beaslbob said:
FWIW years and years ago I and another club member both had extremely low magnesium after years of using instant ocean. like 700-800ppm or so. We were both surprised at how much magnesium it took to get it up to 1300-1500ppm. In both cases it was on the order of pounds of Epsom salts. (and magnesium chloride if you have that.) that was for a 55g size tank. But it worked with no side effects.

For me it was the first step in: http://reefkeeping.com/issues/2006-02/rhf/index.php

my .02

Thanks. So at this point do I keep dosing it until I reach my goal. I just checked it and it has increased to 1230ppm from 1200ppm.

TravisParsley · Aug 23, 2017

I had this issue a long time ago, until I switched salts. I found that trying to dose magnesium to get it high enough for my liking - was extremely hard. I found that in order to get it raised by 100 in my 125 gallon, it took an extraordinary amount of dosing magnesium. I feel the best soultion is to use a salt that already has a high magnesium content. Do some water changes with this salt.

I do want to note that in my experience, raising the mag over 100 in a 24 hr period stressed my corals, most notably mushrooms -they shriveled and took days to get back where they were. Ever since using a higher grade salt, I can dose 100 ml once every month or two and it stays at 1400.

SalinFL · Aug 23, 2017

TravisParsley said:
I had this issue a long time ago, until I switched salts. I found that trying to dose magnesium to get it high enough for my liking - was extremely hard. I found that in order to get it raised by 100 in my 125 gallon, it took an extraordinary amount of dosing magnesium. I feel the best soultion is to use a salt that already has a high magnesium content. Do some water changes with this salt.

I do want to note that in my experience, raising the mag over 100 in a 24 hr period stressed my corals, most notably mushrooms -they shriveled and took days to get back where they were. Ever since using a higher grade salt, I can dose 100 ml once every month or two and it stays at 1400.

What brand of salt did you change to?

DMan · Aug 23, 2017

Randy Holmes-Farley said:
Magnesium is precipitated (e.g., into coral skeletons or abiotic precipitates) at a very rough rate of about 1.5 ppm magnesium for each 17.5 ppm calcium and 2.8 dKH of alkalinity.

So to lose 150 ppm magnesium this way in 3 days means you would have also lost 1,750 ppm of calcium and 280 dKH of alkalinity.

Seems unlikely,

I show the math in a reef question of the day:
https://www.reef2reef.com/threads/r...fication-and-the-big-three-parameters.321163/

I love it when you turn stuff like this into chemistry lessons. So the op mentioned a 2 part mag which sounds right. Could it have been the ratio of the mag sulphate and mag chloride that is the issue.

TravisParsley · Aug 24, 2017

SalinFL said:
What brand of salt did you change to?

Red Sea Coral Pro

Randy Holmes-Farley · Aug 24, 2017

DMan said:
I love it when you turn stuff like this into chemistry lessons. So the op mentioned a 2 part mag which sounds right. Could it have been the ratio of the mag sulphate and mag chloride that is the issue.

Thanks, and no. Using one chemical only will skew the chloride to sulfate ratio, but won't impact the ability to raise magnesium.

Mike Yaniz · Aug 24, 2017

Well I measured correctly 5 cups to 3 cups as it instructed? I think it's time for me to start making my own water. Getting it delivered was so easy. Im going to buy the Red Sea and try it out. Any recommendations where to buy it at a good price? Thanks to you all for your help. Being a newbie isn't so bad thanks to you all.

CodyRVA · Aug 24, 2017

Mike Yaniz said:
Well I measured correctly 5 cups to 3 cups as it instructed? I think it's time for me to start making my own water. Getting it delivered was so easy. Im going to buy the Red Sea and try it out. Any recommendations where to buy it at a good price? Thanks to you all for your help. Being a newbie isn't so bad thanks to you all.

Honestly just shop around. BRS, Marine Depot, Dr. Fosters, Amazon. You might see bad reviews about broken buckets, IME you can pretty much expect this from any supplier; blame it on the shipping.

Jayman · Aug 24, 2017

Mike Yaniz said:
Well I measured correctly 5 cups to 3 cups as it instructed? I think it's time for me to start making my own water. Getting it delivered was so easy. Im going to buy the Red Sea and try it out. Any recommendations where to buy it at a good price? Thanks to you all for your help. Being a newbie isn't so bad thanks to you all.

I would test my new water I bet that has a realy low mag. Level I've read a lot that io has a realy low mag. Count