Magnesium at dangerous levels

lilbitreefer · Nov 22, 2018

Over the last few months I have been dosing magnesium, I being stupid did not check the magnesium enough as I did not have the test kit for it. I have checked it a few times and it remains over 1500. I just checked it with the red sea kit which I heard is the most accurate and it read at 1900. I have quit dosing mag about 2-3 weeks ago. Do I need to do massive water changes to get the mag down or just leave it as is? I added a few new corals and they seem a bit stressed but they were open for the first few days but closed up after that. One has bleached out and died.

Dr. Reef · Nov 22, 2018

Mag levels of 1900 are not dangerous.
People run mag as high as 2100 to fight off algae.
I have personally ran mag as low as 800 to as high as 2300 without any ill effects.
You dont need a massive water change nor any remedies to bring mag down.
You are fine with those numbers and after long period of time it will fall in place.

Coral stress and bleaching is probably related to some other issue.

lilbitreefer · Nov 22, 2018

Oh thanks! I thought it was dangrous high as the highest I have ever seen anyone recomend it to be at 1400. Didn't know about the algae part. That is good to know cause I have an algae problem. Thanks!!!

Dr. Reef · Nov 22, 2018

You're welcome.
Some reef salts mix at 1600 to 1800.

Cory · Nov 22, 2018

It just kills algae so that cant be dangerous.

Id lower it imo.

Randy Holmes-Farley · Nov 23, 2018

lilbitreefer said:
Over the last few months I have been dosing magnesium, I being stupid did not check the magnesium enough as I did not have the test kit for it. I have checked it a few times and it remains over 1500. I just checked it with the red sea kit which I heard is the most accurate and it read at 1900. .

You heard wrong (IMO).

It is by far the most problematic magnesium kit reported by users here. I would not believe it. I'm not sure what the issue with it is, but many reefers get very incorrect answers with it.

Scrubber_steve · Nov 23, 2018

The RedSea mag test kit is fine. I guage it against NSW & its quite accurate.

The trick to using it correctly is, to take the reading at the very first change in color from pink. If you continue to add drops of regeant C past this point, to get the test solution to the blue color as indicated on the test card, you'll get a false high reading.

tenurepro · Nov 24, 2018

Randy Holmes-Farley said:
You heard wrong (IMO).

It is by far the most problematic magnesium kit reported by users here. I would not believe it. I'm not sure what the issue with it is, but many reefers get very incorrect answers with it.

I’ve also had big issues with Redsea’s mag kit; salifert is my go to kit now

LittleMaui · Nov 24, 2018

I have used a Red Sea Mag test kit for 1 1/2 years now. With this test I've averaged 1200-1300. Since the kit is running low, I replaced it with a new Red Sea replacement kit. Now, my Mag tests at 1600. I sent the lot number and expiration date to Red Sea, but they just recommended having my LFS test my Mag, which I plan to do Sunday.

Scrubber_steve · Nov 24, 2018

shaywood said:
I have used a Red Sea Mag test kit for 1 1/2 years now. With this test I've averaged 1200-1300. Since the kit is running low, I replaced it with a new Red Sea replacement kit. Now, my Mag tests at 1600. I sent the lot number and expiration date to Red Sea, but they just recommended having my LFS test my Mag, which I plan to do Sunday.

1 1/2 years... what the expiry date written on the regeant C bottle of your old kit ???

rkpetersen · Nov 24, 2018

The Salifert mag test has a clearer titration endpoint than the Red Sea, is very reproducible, and accurate to within 3% as compared to around 20 concurrent ICP-OES samples.

GoVols · Nov 24, 2018

Randy Holmes-Farley said:
You heard wrong (IMO).

It is by far the most problematic magnesium kit reported by users here. I would not believe it. I'm not sure what the issue with it is, but many reefers get very incorrect answers with it.

+1
Dumped that Red Sea mag kit long ago.

GoVols · Nov 24, 2018

Scrubber_steve said:
The RedSea mag test kit is fine. I guage it against NSW & its quite accurate.

The trick to using it correctly is, to take the reading at the very first change in color from pink. If you continue to add drops of regeant C past this point, to get the test solution to the blue color as indicated on the test card, you'll get a false high reading.

In my opinion it's not trustworthy and have crossed checked against many other kits, when it's been off.

It also takes way too long to preform.

It's a weak link in the Red Sea test kits, to me.

davocean · Nov 24, 2018

I use salifert.

I have elevated my mag pretty high several times w/out issues, and to help rid bryopsis was my reason, but that was w/ kent tech M, as it had something in it that helped rid bryopsis for many people, and only the tech M does or did that to my knowledge(I have heard they may have changed formula)
I would not expect this to clear up most other algae issues for you.

I have had snails seem lethargic from very high levels of mag, but not harmed.

GoVols · Nov 24, 2018

davocean said:
I use salifert.

I have elevated my mag pretty high several times w/out issues, and to help rid bryopsis was my reason, but that was w/ kent tech M, as it had something in it that helped rid bryopsis for many people, and only the tech M does or did that to my knowledge(I have heard they may have changed formula)
I would not expect this to clear up most other algae issues for you.

I have had snails seem lethargic from very high levels of mag, but not harmed.

(lol)
They released the ole Kent - Tech-M formula under the Brightwell's product line.
https://reefbuilders.com/2017/10/27/treating-bryopsis-algae-with-brightwell-aquatics-hydrat-mg/

davocean · Nov 24, 2018

Well that was a good move, it was the only reason I bought Tech M specifically. (Although I now have used flucanzole for the same reason which actually does rid both HA and bry, though I do not advise OP to chase problems by dumping chems unless it really comes down to needing it)

LittleMaui · Nov 24, 2018

Scrubber_steve said:
1 1/2 years... what the expiry date written on the regeant C bottle of your old kit ???

11/2018

Scrubber_steve · Nov 24, 2018

rkpetersen said:
The Salifert mag test has a clearer titration endpoint than the Red Sea, is very reproducible, and accurate to within 3% as compared to around 20 concurrent ICP-OES samples.

In regards to a clearer titration endpoint: In the photo below the difference in color between A and B occurred within one drop of RedSea reagent C being added to the test solution. This is the endpoint,,, it could not be any clearer (1 drop).

Photo C is the endpoint color as shown on the test kit card. The difference in ppm between B and C is around 120ppm.

When I bought this test kit I compared its result to NSW. The magnesium content of natural sea water is around 1290ppm. The Redsea tested at 1320ppm.

Scrubber_steve · Nov 24, 2018

GoVols said:
In my opinion it's not trustworthy and have crossed checked against many other kits, when it's been off.

It also takes way too long to preform.

It's a weak link in the Red Sea test kits, to me.

Fair enough. Keep using what you use. I like the RedSea myself.

I will say that the improvements with the Redsea alkalinity test was dramatic, excellent, as is the case with their PO4 test kit, which is excellent for low range testing.