High Magnesium - 1700+

chatyak · 02/20/2012, 05:57 PM

Tested Reef Crystals at 1.0255 (half way between 1.025 and 1.026) @ 75 F degrees.

Ca: 535
dKH: 11
MG: 1710

MG is rather high isn't it? I don't want my snails to die as I have heard high MG can cause them to waste away...

With that said - I do like the parameters and I understand the MG should be roughly 3x the CA levels and it helps to stabilize PH levels... will it be okay as long as it is done slowly? My entire tank is using Tropic Marin Pro Reef at the moment and it sucked parameter wise. Never buying it again. I changed out 5 gallons (140 gallon total volume roughly)... the issue is I don't want to shock the sytem... currently my alk is around 6 from using TMP and I dont want the sudden blast of of a dKH of 11, and the magnesium issue.

chatyak · 02/20/2012, 07:32 PM

I tested again. MG came to 1560... not sure why the difference... Regardless even if its at 1560 - will this affect my fighting conch and turbo snails?

bertoni · 02/20/2012, 09:50 PM

1560 ppm should be fine. People run tanks at significantly higher levels without problems.

chatyak · 02/21/2012, 12:09 AM

Quote:

Originally Posted by bertoni

1560 ppm should be fine. People run tanks at significantly higher levels without problems.

I could have sworn bertoni I just read an archived post of you saying that snails would suffer at higher ppm.... good to know about the 1560 though. Would you say the same at 1700 as well? I'm changing about 10 gallons of water per day... to switch the tank over from tropic marin's low reading to reef crystals.... it shoudln't shock the tank I don't think?

Randy Holmes-Farley · 02/21/2012, 08:25 AM

It also may not be an accurate magnesium result, or the salinity is higher than you think.

chatyak · 02/21/2012, 02:13 PM

Quote:

Originally Posted by Randy Holmes-Farley

It also may not be an accurate magnesium result, or the salinity is higher than you think.

I calibrated my refractometer with a 35ppt solution.

I will test a 3rd time today and see what it says.

chatyak · 02/21/2012, 08:06 PM

I tested 2 more times today. They were roughly 1510 - 1570 respectively.

So I have 3 readings between 1500-1570 and the 1st result was 1710. Odd.

Salinity was just a sliver above 1.025

bertoni · 02/21/2012, 10:04 PM

The 1500-1570 spread seems reasonable to me, given test kit issues and so on. I'd pick a random number between the limits.

chatyak · 02/22/2012, 12:49 AM

Quote:

Originally Posted by bertoni

The 1500-1570 spread seems reasonable to me, given test kit issues and so on. I'd pick a random number between the limits.

Will a large water change affect things or should I do minor changes over time so as not to shock with the higher dKH and MG etc.. Also - do you think my snails will be okay with MG at that level? I dont know why the test kit showed 1700+ the other time. I'll test again tomorrow to be sure.

Randy Holmes-Farley · 02/22/2012, 06:59 AM

I would just do regular changes over time. That magnesium level doesn't warrant unusual actions, IMO.

antbreon · 02/22/2012, 05:19 PM

if you are changing water and the water you are adding has high..mag..the water you are removing and adding it to is lower so it will blend and average out..as long at the mag in your tank stay in parameters ..i wouldn't worry..

JustAClownFish · 10/27/2017, 06:07 PM

I have the same problem. I use IO at 1.026. Just tested and it's beyond 1700ppm. Is there any way to get this down? I just did a couple water changes last week because I had problems with high mg due to the red sea pro salt mix. I didn't expect to have the same problems with IO.

karimwassef · 10/27/2017, 06:25 PM

doesn't really do any harm. plenty of threads on it.

bertoni · 10/27/2017, 07:57 PM

The only practical to lower the magnesium level is water changes with a lower-magnesium salt. I'd probably just ignore the issue.

JustAClownFish · 10/27/2017, 10:05 PM

I read that inverts struggle with high mg and that some corals might not color up as nicely.

bertoni · 10/27/2017, 10:28 PM

Maybe. I have gotten conflicting reports on that, and I am no longer sure that invertebrates will have problems. Coral coloration is a very difficult subject, and I don't know what the effect, if any, might be, but I haven't heard much negative information.

orcafood · 10/28/2017, 01:54 AM

Ime high magnesium raises the caco3 precipitation point. Not bad but calcifying organisms wont grow as quickly, or at all. Especially if ca is low.

Over all do water changes with a lower mg salt blend. Instant ocean is how I usually drop parameters if need be

mcgyvr · 10/28/2017, 05:59 AM

Seems to be quite a few reports of inconsistencies with Instant Ocean lately (both regular and RC)..
Not sure if its all just measurement error or maybe time to jump ship..

bertoni · 10/28/2017, 03:26 PM

Adding magnesium will tend to drop the rate of abiotic precipitation because magnesium fouls crystals as they form. That's one of the reasons that saltwater can be supersaturated with respect to calcium carbonate.

orcafood · 10/29/2017, 09:22 AM

Interesting I just made 100 gall of IO and it tested perfectly for the big 3

JustAClownFish · 10/29/2017, 04:58 PM

I don't know if the error is on my side. I always have problems with high Mg and sometimes Ca no matter what salt mix I use. I purchased the normal red sea salt mix yesterday. Just mixed a bucket.

They claim for 35ppt:

Ca 430
Mg1280
alk 8

I measured (except for Ca, need a new test kit)

Mg 1500
Alk 9.6

I measured a couple times with Salifert test kits. It's always high. The salinity I triple checked with the Red Sea refractometer. It's exactly 35ppt.

When I use the Coral Pro salt mix I get Mg beyond 1700ppm, Ca around 550, alk 12 -13dkh.

bertoni · 10/30/2017, 01:09 PM

Has the refractometer been tested with a calibration solution? The PinPoint salinity calibration will work, and it's cheap. You can make a calibration solution, too:

http://reefkeeping.com/issues/2004-06/rhf/index.htm

I suspect the issue is a bad batch of salt, though.

five.five-six · 10/30/2017, 01:31 PM

Magnesium sulfate has a much higher refractive index than sodium chloride. You should double check your salinity with a hydrometer.

JustAClownFish · 10/31/2017, 12:01 AM

I have the calibrating solution. It's def. a problem on my side. I calibrate, test the water, and then when I test again it's off. So I don't really know whether the first measurement I took is the accurate one or the second.

@five.five-six

What do you mean by Magnesium sulfate has a higher refractive index than sodium chloride?

bertoni · 10/31/2017, 02:10 PM

A solution that has a large amount of magnesium sulfate in it might have a different refractive index than saltwater, causing it to read inaccurately, but the difference between 1500 ppm and 1275 ppm is too small to have an effect, whether the magnesium is from magnesium chloride or magnesium sulfate.

I'd go with the 1500 ppm measurement, but maybe a local fish store could run a check for you.

02/20/2012, 05:57 PM	#1
chatyak Registered Member Join Date: May 2006 Posts: 2,090	High Magnesium - 1700+ Tested Reef Crystals at 1.0255 (half way between 1.025 and 1.026) @ 75 F degrees. Ca: 535 dKH: 11 MG: 1710 MG is rather high isn't it? I don't want my snails to die as I have heard high MG can cause them to waste away... With that said - I do like the parameters and I understand the MG should be roughly 3x the CA levels and it helps to stabilize PH levels... will it be okay as long as it is done slowly? My entire tank is using Tropic Marin Pro Reef at the moment and it sucked parameter wise. Never buying it again. I changed out 5 gallons (140 gallon total volume roughly)... the issue is I don't want to shock the sytem... currently my alk is around 6 from using TMP and I dont want the sudden blast of of a dKH of 11, and the magnesium issue. __________________ Fishville Last edited by chatyak; 02/20/2012 at 06:02 PM. Reason: typo

02/20/2012, 07:32 PM	#2
chatyak Registered Member Join Date: May 2006 Posts: 2,090	I tested again. MG came to 1560... not sure why the difference... Regardless even if its at 1560 - will this affect my fighting conch and turbo snails? __________________ Fishville

02/20/2012, 09:50 PM	#3
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	1560 ppm should be fine. People run tanks at significantly higher levels without problems. __________________ Jonathan Bertoni

02/21/2012, 08:25 AM	#5
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	It also may not be an accurate magnesium result, or the salinity is higher than you think. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

02/21/2012, 08:06 PM	#7
chatyak Registered Member Join Date: May 2006 Posts: 2,090	I tested 2 more times today. They were roughly 1510 - 1570 respectively. So I have 3 readings between 1500-1570 and the 1st result was 1710. Odd. Salinity was just a sliver above 1.025 __________________ Fishville

02/21/2012, 10:04 PM	#8
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	The 1500-1570 spread seems reasonable to me, given test kit issues and so on. I'd pick a random number between the limits. __________________ Jonathan Bertoni

02/22/2012, 06:59 AM	#10
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	I would just do regular changes over time. That magnesium level doesn't warrant unusual actions, IMO. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

02/22/2012, 05:19 PM	#11
antbreon Registered Member Join Date: Nov 2011 Location: port stlucie fla Posts: 187	if you are changing water and the water you are adding has high..mag..the water you are removing and adding it to is lower so it will blend and average out..as long at the mag in your tank stay in parameters ..i wouldn't worry..

10/27/2017, 06:07 PM	#12
JustAClownFish Registered Member Join Date: Oct 2017 Location: California Posts: 226	I have the same problem. I use IO at 1.026. Just tested and it's beyond 1700ppm. Is there any way to get this down? I just did a couple water changes last week because I had problems with high mg due to the red sea pro salt mix. I didn't expect to have the same problems with IO.

10/27/2017, 06:25 PM	#13
karimwassef Registered Member Join Date: May 2004 Location: Dallas, TX Posts: 11,033	doesn't really do any harm. plenty of threads on it. __________________ Failure isn't an option It's a requirement. 660g 380inwall+280smp/surge S/L/Soft/Maxima/RBTA/Clown/Chromis/Anthias/Tang/Mandarin/Jawfish/Goby/Wrasse/D'back. DIY 12' Skimmer ActuatedSurge ConcreteScape

10/27/2017, 07:57 PM	#14
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	The only practical to lower the magnesium level is water changes with a lower-magnesium salt. I'd probably just ignore the issue. __________________ Jonathan Bertoni

10/27/2017, 10:05 PM	#15
JustAClownFish Registered Member Join Date: Oct 2017 Location: California Posts: 226	I read that inverts struggle with high mg and that some corals might not color up as nicely.

10/27/2017, 10:28 PM	#16
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Maybe. I have gotten conflicting reports on that, and I am no longer sure that invertebrates will have problems. Coral coloration is a very difficult subject, and I don't know what the effect, if any, might be, but I haven't heard much negative information. __________________ Jonathan Bertoni

10/28/2017, 01:54 AM	#17
orcafood Registered Member Join Date: Nov 2007 Location: Raleigh Posts: 864	Ime high magnesium raises the caco3 precipitation point. Not bad but calcifying organisms wont grow as quickly, or at all. Especially if ca is low. Over all do water changes with a lower mg salt blend. Instant ocean is how I usually drop parameters if need be __________________ Acros, Zoas, Lps and Acros Kevin Current Tank Info: 200 gallon sps

10/28/2017, 05:59 AM	#18
mcgyvr Registered Member Join Date: Sep 2003 Location: North Carolina Posts: 20,050	Seems to be quite a few reports of inconsistencies with Instant Ocean lately (both regular and RC).. Not sure if its all just measurement error or maybe time to jump ship.. __________________ Who me?

10/28/2017, 03:26 PM	#19
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Adding magnesium will tend to drop the rate of abiotic precipitation because magnesium fouls crystals as they form. That's one of the reasons that saltwater can be supersaturated with respect to calcium carbonate. __________________ Jonathan Bertoni

10/29/2017, 09:22 AM	#20
orcafood Registered Member Join Date: Nov 2007 Location: Raleigh Posts: 864	Interesting I just made 100 gall of IO and it tested perfectly for the big 3 __________________ Acros, Zoas, Lps and Acros Kevin Current Tank Info: 200 gallon sps Last edited by orcafood; 10/29/2017 at 09:29 AM.

10/29/2017, 04:58 PM	#21
JustAClownFish Registered Member Join Date: Oct 2017 Location: California Posts: 226	I don't know if the error is on my side. I always have problems with high Mg and sometimes Ca no matter what salt mix I use. I purchased the normal red sea salt mix yesterday. Just mixed a bucket. They claim for 35ppt: Ca 430 Mg1280 alk 8 I measured (except for Ca, need a new test kit) Mg 1500 Alk 9.6 I measured a couple times with Salifert test kits. It's always high. The salinity I triple checked with the Red Sea refractometer. It's exactly 35ppt. When I use the Coral Pro salt mix I get Mg beyond 1700ppm, Ca around 550, alk 12 -13dkh.

10/30/2017, 01:09 PM	#22
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Has the refractometer been tested with a calibration solution? The PinPoint salinity calibration will work, and it's cheap. You can make a calibration solution, too: http://reefkeeping.com/issues/2004-06/rhf/index.htm I suspect the issue is a bad batch of salt, though. __________________ Jonathan Bertoni

10/30/2017, 01:31 PM	#23
five.five-six Registered Member Join Date: Mar 2007 Location: Corona Posts: 7,827 Blog Entries: 6	Magnesium sulfate has a much higher refractive index than sodium chloride. You should double check your salinity with a hydrometer. __________________ Originally posted by yellowslayer13: "I hate that hole" Current Tank Info: SCMAS Member 225 peninsula euroreef RS180 Apex 400W X 3 20k radiums / Spectra mixed SPS

10/31/2017, 12:01 AM	#24
JustAClownFish Registered Member Join Date: Oct 2017 Location: California Posts: 226	I have the calibrating solution. It's def. a problem on my side. I calibrate, test the water, and then when I test again it's off. So I don't really know whether the first measurement I took is the accurate one or the second. @five.five-six What do you mean by Magnesium sulfate has a higher refractive index than sodium chloride?

10/31/2017, 02:10 PM	#25
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	A solution that has a large amount of magnesium sulfate in it might have a different refractive index than saltwater, causing it to read inaccurately, but the difference between 1500 ppm and 1275 ppm is too small to have an effect, whether the magnesium is from magnesium chloride or magnesium sulfate. I'd go with the 1500 ppm measurement, but maybe a local fish store could run a check for you. __________________ Jonathan Bertoni