Randys 2 Part - Magnesium

Saltyd@wg · Feb 21, 2017

I currently have a CA reactor set up on my tank...Alkalinity holds fast at 172 ppm
I'm finding that I am adding approx 22 oz of mg every 11 days or so to keep my Magnesium in around 1320 ppm
Does this seem high? In any case I want to automate it...
Simple math would be 2 oz per day...Does it work like this or is there a compounding factor
Let me know what you think...thx

Randy Holmes-Farley · Feb 21, 2017

I can't tell if it is a lot since I don't know the tank size, but spreading it out like that is fine.

You are using the ~10:1 ratio chloride to sulfate?

redfishbluefish · Feb 21, 2017

How old is your test kit.....and whose kit is it? I found that went my Red Sea Mag test kit expired, and then some, I'd always get the same low number....in the 1300's. After adding half a gallon, still 1300's. So double check with a friend's kit or an LFS to make sure you have the right Mag number.

Saltyd@wg · Feb 21, 2017

I'm using Recipe #1 Part 3A
Tank is 155 gallon mixed
Test kit is Sailfert and is not old..
I've been experiencing this drop in mg for some time now...and my calculator bring it right back up to spec meaning if I want it to go up to 1320 I add what it says, and tomorrow it indicates 1320

redfishbluefish · Feb 21, 2017

What salt are you using....that just seems like a bunch of magnesium. Again, I'd have someone else test to verify your numbers.

Saltyd@wg · Feb 21, 2017

Instant ocean - orange "reef crystals"
I agree, it sounds like a ton of magnesium as well but I'm not sure what the draw is as I'm guessing the 2 part may be diluted to a point where it makes sense...
I'll test it again but thinking out loud, if the test kit was the issue, it would never test correctly...in my case it drops I dose according to my calculator and it brings it right back up to spec
Weired

Kyle Rinker · Feb 21, 2017

How often are you doing water changes? I have found that while salts like IO are fine and cost effective, they tend to skimp on magnesium. Effectively, every time you do a water change, you could actually be lowering your magnesium.

redfishbluefish · Feb 21, 2017

Kyle Rinker said:
How often are you doing water changes? I have found that while salts like IO are fine and cost effective, they tend to skimp on magnesium. Effectively, every time you do a water change, you could actually be lowering your magnesium.

But here's the thing.....he's not just using Instant Ocean, he's using Reef Crystals which should be over 1400 ppm at 1.026 salinity.

And that's what the OP needs to do.....With a fresh batch of saltwater, test the magnesium level. At 1.026 salinity, it should be 1440.

Kyle Rinker · Feb 21, 2017

I agree it should be. Was there a statement of what the specific gravity was kept at? I may have just missed it. Either way, I had one batch of Instant Ocean salt that was well below their stated specs for magnesium, closer to 1200. My other boxes of salt have been just fine.

Randy Holmes-Farley · Feb 22, 2017

Saltyd@wg said:
I'm using Recipe #1 Part 3A
Tank is 155 gallon mixed
Test kit is Sailfert and is not old..
I've been experiencing this drop in mg for some time now...and my calculator bring it right back up to spec meaning if I want it to go up to 1320 I add what it says, and tomorrow it indicates 1320

It isn't related to any issues in this thread, but a better recipe when using a CaCO3/CO2 rector for calcium and alkalinity is given here:

Do-It-Yourself Magnesium Supplements for the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-07/rhf/index.php

from it:

Using both Epsom salts and MAG flake, dissolve 7¼ cups MAG flake and ¾ cup Epsom salts in one gallon of water, and use that to supplement magnesium in amounts determined using this linked online calculator, with the entry "Randy's Recipes 1 and 2 Versions A and B," and ignore for this purpose what those designations mean. This recipe is preferred, but its advantage over recipe #2 is minimal in most cases.

Note that combining the two materials in solution can result in some precipitation of calcium sulfate (calcium and sulfate are impurities in the MAG flake and the Epsom salts, respectively. To assure yourself that the two materials have fully dissolved, dissolve each separately in some freshwater before combining them. Some calcium sulfate precipitation is acceptable, and it is okay to let the solids get into the aquarium, assuming you can dose in a way that prevents them from landing on delicate organisms.

Note also that this recipe (#3) is different from that given in my DIY two-part recipe, because in that case more magnesium sulfate is necessary to offset the rise in chloride that is provided by both the calcium chloride and the magnesium chloride.

Randy Holmes-Farley · Feb 22, 2017

You are adding a bit under 5 ppm per day. That seems high, but it might take a long time to distinguish that from 2 ppm per day with a normal magnesium kit.

How much alk do you think your reactor adds each day? Any idea?

Saltyd@wg · Feb 22, 2017

I'm adding 1.4 ml per minute so a very slow drip rate

My alkalinity is sitting at 173 ppm (9.728 dkh) and has been climbing at about 1 ppm per week...I raised the level in the ph controller a hair hopefully that will make a difference but probably won't see it till today

I've read articles that this level is a little high but acceptable...I would be it has the direct effect on the calcium making it a little low...Someone mentioned to me that this would also have an affect on my Magnesium is generally 3 times

Saltyd@wg · Feb 22, 2017

Randy Holmes-Farley said:
It isn't related to any issues in this thread, but a better recipe when using a CaCO3/CO2 rector for calcium and alkalinity is given here:

Do-It-Yourself Magnesium Supplements for the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-07/rhf/index.php

from it:

Using both Epsom salts and MAG flake, dissolve 7¼ cups MAG flake and ¾ cup Epsom salts in one gallon of water, and use that to supplement magnesium in amounts determined using this linked online calculator, with the entry "Randy's Recipes 1 and 2 Versions A and B," and ignore for this purpose what those designations mean. This recipe is preferred, but its advantage over recipe #2 is minimal in most cases.

Note that combining the two materials in solution can result in some precipitation of calcium sulfate (calcium and sulfate are impurities in the MAG flake and the Epsom salts, respectively. To assure yourself that the two materials have fully dissolved, dissolve each separately in some freshwater before combining them. Some calcium sulfate precipitation is acceptable, and it is okay to let the solids get into the aquarium, assuming you can dose in a way that prevents them from landing on delicate organisms.

Note also that this recipe (#3) is different from that given in my DIY two-part recipe, because in that case more magnesium sulfate is necessary to offset the rise in chloride that is provided by both the calcium chloride and the magnesium chloride.

---------------------

Thanks...I will change it up...I'm guessing the calculation is almost the same as the one I have been using (The link to the online calculator seems to be broken)

Randy Holmes-Farley · Feb 22, 2017

The calcium concentration of the additives is exactly the same between the two recipes, but one has less chloride and more sulfate as counterions. The reason is to offset the chloride added with calcium chloride.

"I've read articles that this level is a little high but acceptable...I would be it has the direct effect on the calcium making it a little low...Someone mentioned to me that this would also have an affect on my Magnesium is generally 3 times"

If you are suggesting the high alk is making magnesium drop, no, that is not the explanation for excessive magnesium demand relative to alkalinity demand.

Saltyd@wg · Feb 23, 2017

[QUOTE="
If you are suggesting the high alk is making magnesium drop, no, that is not the explanation for excessive magnesium demand relative to alkalinity demand.[/QUOTE]

Trying to over think it..if my Alkalinity is a little high, then my CA is a little low...Somebody mentioned that there was a direct correlation between CA level and MG level...maybe that works if doing regular water changes or something...

My biggest fear in all this is that I'm overdoing the MG and stuff will die...

Anyway, will keep testing...

Thanks

Randy Holmes-Farley · Feb 23, 2017

Saltyd@wg said:
Trying to over think it..if my Alkalinity is a little high, then my CA is a little low...Somebody mentioned that there was a direct correlation between CA level and MG level...maybe that works if doing regular water changes or something...

No, that is not true and is why it is so bad to oversimplify reef chemistry to the point where people draw incorrect conclusions.