Magnesium continues to increase without supplementation.

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
I'm having an issue where magnesium continues to go up over a period of time.

It was reading at around 1700 during November 2019 and I did a 90% water change to bring it back down to 1490. My corals were doing awful at the 1700 marker, especially LPS corals, and afterwards they started to recover.

I checked Magnesium once again 1/8/20 and it was now at 1550. Today it's slowly climbed back up to 1680 and the corals are looking awful again. I'm using ESV two part for alkalinity and calcium but I'm not dosing for magnesium. My tank consumes about 1.2 dkh over a period of 7 days. Calcium is much slower. I would expect magnesium to drop very slowly as well but its actually going up.

Alk is currenly sitting at 7.90 dkh
Calcium is currently sitting at 440

These Mag tests were done on saliferts and redsea test kits which aren't expected to be expired till about 2022. Both are reading about +/- 5 of each other.

I've done no water changes since that 90% water change.

I've checked my TDS meter on my 4 stage RO/DI unit and its reading 0.

If anyone else has any ideas on where magnesium is coming from or I'm totally missing something, let me know. I'd like to fix it and avoid any more water changes.

I'm not a big fan of water changes because I'm a small guy. I mean a 5 gallon bucket of water is almost 40% of my body weight. lol. Also this tank is 144 miles from the closest LFS so I can't get anyone out here either to do it for me.
 

Hemmdog

10K Club member
View Badges
Joined
Dec 9, 2018
Messages
11,681
Reaction score
44,772
Location
Silicon Valley, CA
Rating - 0%
0   0   0
I believe there is some mag in the calcium part of esv’s 2 part. Your alk is too low for the big 3 to be in balance for consumption. Dose alk up to 9 and don’t dose calcium until it drops below 420. This should help corals start consuming again. Which will lower your mag. That’s what I would do.
 
OP
OP
tankstudy

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
I believe there is some mag in the calcium part of esv’s 2 part. Your alk is too low for the big 3 to be in balance for consumption. Dose alk up to 9 and don’t dose calcium until it drops below 420. This should help corals start consuming again. Which will lower your mag. That’s what I would do.

Both alk and calcium are being taken up but magnesium is increasing at a rate far faster than it's being consumed. I've used ESV two parts for about 5-6 years now and I feel the two parts alone shouldn't increase magnesium by such a number over time...unless they've done something to their product.

At the same time, during the recovering phase from November to January there was No dosing at all but magnesium still crept up.
 
OP
OP
tankstudy

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
I was wondering if this is possible

TDS reader shows 0 ppm but can it be something like this:
  • 0 ppm Sodium
  • 0 ppm Potassium
  • 0 ppm Calcium
  • 1-2 ppm Magnesium
  • 0 ppm CaCO3 (total hardness)
  • 0 ppm Chloride
  • 0 ppm Sulfate
I could get a Magnesium test kit for freshwater.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
I was wondering if this is possible

TDS reader shows 0 ppm but can it be something like this:
  • 0 ppm Sodium
  • 0 ppm Potassium
  • 0 ppm Calcium
  • 1-2 ppm Magnesium
  • 0 ppm CaCO3 (total hardness)
  • 0 ppm Chloride
  • 0 ppm Sulfate
I could get a Magnesium test kit for freshwater.

no, and even if it was, if you evaporate 1% per day, that boosts magnesium by 0.01 to 0.02 ppm per day.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
I'm having an issue where magnesium continues to go up over a period of time.

It was reading at around 1700 during November 2019 and I did a 90% water change to bring it back down to 1490. My corals were doing awful at the 1700 marker, especially LPS corals, and afterwards they started to recover.

I checked Magnesium once again 1/8/20 and it was now at 1550. Today it's slowly climbed back up to 1680 and the corals are looking awful again. I'm using ESV two part for alkalinity and calcium but I'm not dosing for magnesium. My tank consumes about 1.2 dkh over a period of 7 days. Calcium is much slower. I would expect magnesium to drop very slowly as well but its actually going up.

Alk is currenly sitting at 7.90 dkh
Calcium is currently sitting at 440

These Mag tests were done on saliferts and redsea test kits which aren't expected to be expired till about 2022. Both are reading about +/- 5 of each other.

I've done no water changes since that 90% water change.

I've checked my TDS meter on my 4 stage RO/DI unit and its reading 0.

If anyone else has any ideas on where magnesium is coming from or I'm totally missing something, let me know. I'd like to fix it and avoid any more water changes.

I'm not a big fan of water changes because I'm a small guy. I mean a 5 gallon bucket of water is almost 40% of my body weight. lol. Also this tank is 144 miles from the closest LFS so I can't get anyone out here either to do it for me.

I expect it is test error, which is very common with magnesium kits, especially Red Sea.

the other reasonable alternative is salinity changes. Magnesium can appear to rise and fall a lot due to salinity changes.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
I believe there is some mag in the calcium part of esv’s 2 part. Your alk is too low for the big 3 to be in balance for consumption. Dose alk up to 9 and don’t dose calcium until it drops below 420. This should help corals start consuming again. Which will lower your mag. That’s what I would do.

That doesn’t make sense to me. His alk and calcium numbers are perfect and elevated magnesium (assuming it is real) is not known to inhibit coral calcification.
 
OP
OP
tankstudy

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
The changes appear on both redsea and saliferts.

As for salinity changes, are you talking like large swings or smaller? Using the hanna salinity tester at most in 2 weeks it may shift 0.5 ppt. Salinity generally drops from 35 ppt. to about 34.5 ppt.
 

Hemmdog

10K Club member
View Badges
Joined
Dec 9, 2018
Messages
11,681
Reaction score
44,772
Location
Silicon Valley, CA
Rating - 0%
0   0   0
That doesn’t make sense to me. His alk and calcium numbers are perfect and elevated magnesium (assuming it is real) is not known to inhibit coral calcification.
My goal was trying to get his alk, cal, and magnesium back in a better ratio of each other so the tank could consume the higher magnesium levels.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
My goal was trying to get his alk, cal, and magnesium back in a better ratio of each other so the tank could consume the higher magnesium levels.

But the levels are currently perfect. Alk at 7.9 dKH and calcium at 440 ppm.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
The changes appear on both redsea and saliferts.

As for salinity changes, are you talking like large swings or smaller? Using the hanna salinity tester at most in 2 weeks it may shift 0.5 ppt. Salinity generally drops from 35 ppt. to about 34.5 ppt.

I still expect it is not real. 95% of elevated magnesium issues turn out to be test error. The other 5% are high salinity or an off salt mix.

what is your substrate made of? Rock type?

No other additives at all?
 
OP
OP
tankstudy

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
Also thanks for the reply.

I'm pretty confused on the current situation.
I still expect it is not real. 95% of elevated magnesium issues turn out to be test error. The other 5% are high salinity or an off salt mix.

what is your substrate made of? Rock type?

No other additives at all?

Rock - Two little fishies Stax Porous Oolitic Dry Rock.
Substrate - Bahamas Oolite Live Sand

As for salt it's Instant Ocean. It was used up to the point of the 1700 issue and was used as the 90% water change which brought it back down to 1490. Same box/lot.

No magnesium additives at all. Just ESV alk and calc. Magnesium hasn't been dosed or near the tank since I first discovered the issue.

I'll rerun the Mag test on a fresh batch of salt water as soon as I get home.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
66,553
Reaction score
62,858
Location
Arlington, Massachusetts, United States
Rating - 0%
0   0   0
Maybe the ESV product got mislabeled and the calcium product is actually their magnesium product.
You might take some new salt water, measure magnesium, then boost calcium by 100 ppm in it and remeasure magnesium in it.
 

Smarkow

Valuable Member
View Badges
Joined
Jan 3, 2018
Messages
1,195
Reaction score
2,452
Location
Toledo
Rating - 0%
0   0   0
Also thanks for the reply.

I'm pretty confused on the current situation.


Rock - Two little fishies Stax Porous Oolitic Dry Rock.
Substrate - Bahamas Oolite Live Sand

As for salt it's Instant Ocean. It was used up to the point of the 1700 issue and was used as the 90% water change which brought it back down to 1490. Same box/lot.

No magnesium additives at all. Just ESV alk and calc. Magnesium hasn't been dosed or near the tank since I first discovered the issue.

I'll rerun the Mag test on a fresh batch of salt water as soon as I get home.
I actually have the same slow Mag trickle up, see below.
611AA1DC-76F2-4E8B-9626-DB87690CFF45.jpeg

I also use STAX and am very happy with them. But I am not sure how STAX are harvested or manufactured/prepared... if anyone knows I would be very interested to hear.

This post is certainly anecdotal in nature, or could be “correlation vs causation.” So someone smarter than me feel free to clarify :)
 
OP
OP
tankstudy

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
Maybe the ESV product got mislabeled and the calcium product is actually their magnesium product.
You might take some new salt water, measure magnesium, then boost calcium by 100 ppm in it and remeasure magnesium in it.

I'll try that.

New fresh saltwater batch reads 1420.

Based off Instant Ocean's product description at 35 ppt:

Instant Ocean® should provide a solution that has 400 mg/L calcium ion and 1320 mg/L magnesium ion

So off by about 100?
 

Smarkow

Valuable Member
View Badges
Joined
Jan 3, 2018
Messages
1,195
Reaction score
2,452
Location
Toledo
Rating - 0%
0   0   0
I'll try that.

New fresh saltwater batch reads 1420.

Based off Instant Ocean's product description at 35 ppt:

Instant Ocean® should provide a solution that has 400 mg/L calcium ion and 1320 mg/L magnesium ion

So off by about 100?
Let's say your Mg really started at 1700 (ie assume no testing errors) and you do regular water changes with instant ocean which advertises as 1320, and sometimes their mag is higher at 1420 because of natural variations... your tank would still come down from 1700 and level off somewhere between 1320-1420. Mag creeping up is either something being added/leeched or a measurement error.

It's not the salt mix my friend :/

I do wonder if it is the STAX tho? I'm gonna try and read more about their harvesting/manufacturing process now
 

Smarkow

Valuable Member
View Badges
Joined
Jan 3, 2018
Messages
1,195
Reaction score
2,452
Location
Toledo
Rating - 0%
0   0   0
Okay, the quick google tells me STAX are mined limestone Oolite
Wikipedia tells me Oolite (for egg) is sedimentary rock formed from concentric spheric layers of (in no particular order) phosphate, clay, chert, DOLOMITE, or iron minerals.
Yes the same dolomite (Calcium Magnesium Carbonate) we often use in calcium reactors for Mg addition.
But at tank pH my guess would be that the Mg addition from quarried limestone is minimal?
Thoughts?
 
OP
OP
tankstudy

tankstudy

Valuable Member
View Badges
Joined
Apr 22, 2014
Messages
1,769
Reaction score
1,508
Rating - 0%
0   0   0
So pushing calcium up 100 ppm with ESV doesn't seem to change magnesium. It reads 1420 still.

Okay, the quick google tells me STAX are mined limestone Oolite
Wikipedia tells me Oolite (for egg) is sedimentary rock formed from concentric spheric layers of (in no particular order) phosphate, clay, chert, DOLOMITE, or iron minerals.
Yes the same dolomite (Calcium Magnesium Carbonate) we often use in calcium reactors for Mg addition.
But at tank pH my guess would be that the Mg addition from quarried limestone is minimal?
Thoughts?

My sand is also Oolite...
 
Back
Top