Salt causing high Zinc/Aluminium levels?

Japtastic

Active Member
View Badges
Joined
May 21, 2018
Messages
260
Reaction score
194
Location
London, UK
Rating - 0%
0   0   0
I have been fighting high zinc levels for the last few months and didn't even consider the salt that I had changed to (Instant Ocean) over that period might be to be to blame. I'm more concerned about the Zinc at this time as Aluminium has come down although there is a ? over where this high level came from. All other ICP pollutants are at undetectable levels.

I have checked everything with a fine tooth comb. All equipment is just under a year old.

2x Jebao 15000 lp/h return pumps. Inspected and no signs of any corrosion.
1x Reef Octopus Skimmer Varios 8. Inspected and no signs of any corrosion.
2x Schego Heaters. No sign of any corrosion even under the caps.
2x MP40's All fully taken apart and look perfect.

Thoroughly searched the tank and sump for any rusting hinges / screws / brackets etc. The only metal I found was a jubilee clip well above the water with zero corrosion but removed it anyway. This clearly wasn't the issue as the next test came back with higher zinc levels again. I have no screen top.

ICP results:

Aluminium:

10/10/18 = 11.5 ug/l
11/12/18 = 122 ug/l !!
30/1/19 = 55 ug/l !

Zinc:

10/10/18 = 9.32 ug/l
11/12/18 = 52.29 ug/l !!

30% Water change + Added Cuprisorb

30/1/19 = 70.89 ug/l !!!

Continued Cuprisorb + added external canister filter @ 1400 lp/h full of Polyfilter media that I have been keeping an eye on and renewing.

During this time I have been adding SPS, which strangely have been doing fine and all 10 frags show signs of growth and decent polyp extension. The LPS and Zoas are a different story. They have been around 50% of the size they normally were before these issues and have been closing fully up randomly during the day.

I was about to do another 30% water change in the next few days before another ICP in a couple weeks but this takes a bit of planning and time when you are making nearly 100 gallons. RODI machine on for around 12-14 hours and a big container in the living room which the wife loves :D

I was searching about similar problems that others have had and there has been a suggestion that certain salt can have elevated levels of pollutants and I came across these tests. This was posted on April 2017 and so may not be relevant to the current production methods or batches but...

https://reefhub.pl/test-of-marine-salts/

io.JPG


Guess which salt has one of the highest if not the highest Aluminum and Zinc? Yes, Instant Ocean.

Zn = 126.66 ug/l !!!
Al = 9.81 ug/l

Clearly, I'm going to get different salt before a water change but Instant Ocean seems to be fairly popular and so you'd expect everyone to have the same problems?

Thoughts?
 

Ranjib

7500 Club Member
View Badges
Joined
Apr 16, 2016
Messages
9,876
Reaction score
16,680
Location
Pleasant Hill, Concord
Rating - 0%
0   0   0
I am using instant ocean for almost 3 years now without any issue. I would not recommend doing large water changes unless you see something is bad (livestock wise). Instant ocean is probably one of the most popular salt out there.. lets see what others say,. You are sure theres no equipment or anything that would cause this?
 
OP
OP
Japtastic

Japtastic

Active Member
View Badges
Joined
May 21, 2018
Messages
260
Reaction score
194
Location
London, UK
Rating - 0%
0   0   0
I wouldn't be too worried but 70 ug/l is fairly high and my LPS don't seem to be a fan of this level. I wouldn't consider 100 gallons or 25-30% water change that large. Maybe I have a bad batch of salt or it matches the test results as found by the marine biologist above? Just coincidence that I have elevated levels and IO tested crazy high for Zinc in the tests and this all started happening

I really have searched high and low for the source of any extra Zinc getting into the system but am drawing a blank.

The only other option is that Zinc is leaching from PVC pipes and the float glass but I would have expected a high reading on my very first ICP which was when the tank was 8 months old...
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
89,263
Reaction score
92,306
Location
Massachusetts, United States
Rating - 0%
0   0   0

Did changing salts fix the zinc contamination or did you figure out something else?
Are you having an issue?

I don’t think his issue (years ago now) was the salt. Studies do not show this to be an an issue.
 

Tikki

Active Member
View Badges
Joined
Jul 8, 2025
Messages
158
Reaction score
142
Location
Pensacola
Rating - 0%
0   0   0

Did changing salts fix the zinc contamination or did you figure out something else?
Are you having an issue?

I don’t think his issue (years ago now) was the salt. Studies do not show this to be an an issue.
Yes, I have been chasing a similar issue. Should I go into detail here or move to a new thread?
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
89,263
Reaction score
92,306
Location
Massachusetts, United States
Rating - 0%
0   0   0
Yes, I have been chasing a similar issue. Should I go into detail here or move to a new thread?

Here is ok. What levels do you observe and is that in the tank, or in new salt water?

Aluminum is often from white media of various sorts, and zinc can be from metal parts in the water, or zinc in plastics used.
 

Tikki

Active Member
View Badges
Joined
Jul 8, 2025
Messages
158
Reaction score
142
Location
Pensacola
Rating - 0%
0   0   0
Here is ok. What levels do you observe and is that in the tank, or in new salt water?

Aluminum is often from white media of various sorts, and zinc can be from metal parts in the water, or zinc in plastics used.

Thanks. Here's my timeline. I'll follow up with some photos of the tank. I use instant ocean reef crystals and do weekly 20% water changes. I use AFR on a dosing pump.


The zinc timeline (µg/L)

  • Mid-August (ATI ICP): Aquarium Zn 0.57 (aluminum ~4 µg/L). RO Zn 0
  • September (ATI ICP): Aquarium Zn 69.43 and RO Zn 10.45.
    • Biggest change between August and September: we added a 3-stage whole-house filter because our city water looked visibly contaminated. Stages were sediment → KDF → carbon (ACB). We also installed fresh SED/GAC/ACB/DI on the RO/DI around that time.
    • Ran CupriSorb in a bag in the sump for 7-10 days
    • Cleaned out mixing bucket
  • October (Triton ICP): Aquarium Zn 4.0 (!). No RO sample submitted with Triton.
  • November (ATI ICP): Aquarium Zn 90.89 and RO Zn 1.24
Since then, we’ve:
  • Ran Metasorb and CupriSorb for about a week each
  • Removed the KDF in whole house filter completely and replaced it with a second ACB
  • Removed one small ceramic bead bag from the sump.
  • Removed an old Hydor Koralia from the refugium.
  • Replaced heater with dual BRS titanium tubes.

Questions:

  • If these zinc levels are at all true, should I expect to see things obviously suffering? We have acros, a clam, shrimp, clean up crew, mixed corals.
  • Even if RO level was 10ug/L, I don’t understand how the tank jumped from 0 to 69 that quickly unless the RO/whole-house situation was briefly much worse than what we sampled, or there’s another source. By November ATI says RO is low (~1.2), but the tank is higher (~90).
  • Is there some reason why the ATI test would come in artificially high, or the Triton artificially low? It's hard to imagine the zinc has swung that much. I have a bottle of detox, but I have not ever used it
  • I have been growing Phytoplankton in this RO water very successfully since early November. Would the zinc levels we're seeing in the RO affect that?
  • I have two ATI tests in hand. I'm preparing to sample this week. Should I send one off from my mixing bucket? What if I took the "RO" sample portion that's included with one of the tests from the mixing bucket instead, or would that not work because it's salty?
 

Tikki

Active Member
View Badges
Joined
Jul 8, 2025
Messages
158
Reaction score
142
Location
Pensacola
Rating - 0%
0   0   0
Here is ok. What levels do you observe and is that in the tank, or in new salt water?

Aluminum is often from white media of various sorts, and zinc can be from metal parts in the water, or zinc in plastics used.

Thanks. Here's my timeline. I'll follow up with some photos of the tank. I use instant ocean reef crystals and do weekly 20% water changes. I use AFR on a dosing pump.


The zinc timeline (µg/L)

  • Mid-August (ATI ICP): Aquarium Zn 0.57 (aluminum ~4 µg/L). RO Zn 0
  • September (ATI ICP): Aquarium Zn 69.43 and RO Zn 10.45.
    • Biggest change between August and September: we added a 3-stage whole-house filter because our city water looked visibly contaminated. Stages were sediment → KDF → carbon (ACB). We also installed fresh SED/GAC/ACB/DI on the RO/DI around that time.
    • Ran CupriSorb in a bag in the sump for 7-10 days
    • Cleaned out mixing bucket
  • October (Triton ICP): Aquarium Zn 4.0 (!). No RO sample submitted with Triton.
  • November (ATI ICP): Aquarium Zn 90.89 and RO Zn 1.24
Since then, we’ve:
  • Ran Metasorb and CupriSorb for about a week each
  • Removed the KDF in whole house filter completely and replaced it with a second ACB
  • Removed one small ceramic bead bag from the sump.
  • Removed an old Hydor Koralia from the refugium.
  • Replaced heater with dual BRS titanium tubes.

Questions:

  • If these zinc levels are at all true, should I expect to see things obviously suffering? We have acros, a clam, shrimp, clean up crew, mixed corals.
  • Even if RO level was 10ug/L, I don’t understand how the tank jumped from 0 to 69 that quickly unless the RO/whole-house situation was briefly much worse than what we sampled, or there’s another source. By November ATI says RO is low (~1.2), but the tank is higher (~90).
  • Is there some reason why the ATI test would come in artificially high, or the Triton artificially low? It's hard to imagine the zinc has swung that much. I have a bottle of detox, but I have not ever used it
  • I have been growing Phytoplankton in this RO water very successfully since early November. Would the zinc levels we're seeing in the RO affect that?
  • I have two ATI tests in hand. I'm preparing to sample this week. Should I send one off from my mixing bucket? What if I took the "RO" sample portion that's included with one of the tests from the mixing bucket instead, or would that not work because it's salty?
20251221_102925_5F7FDDA5-A0A4-491D-AF60-158C3E30A64E.png

20251221_102927_4A192B54-E78D-47A4-94A8-BC5DF5263E51.png

20251221_102929_65E6F822-1310-40A1-8BA0-6C080CF490FB.png

20251221_102930_DBC10977-4ECE-4865-BB93-C8BED0812BF5.png
 

Freenow54

5000 Club Member
View Badges
Joined
Mar 5, 2021
Messages
6,576
Reaction score
5,096
Location
Ontario Canada
Rating - 0%
0   0   0
I have been fighting high zinc levels for the last few months and didn't even consider the salt that I had changed to (Instant Ocean) over that period might be to be to blame. I'm more concerned about the Zinc at this time as Aluminium has come down although there is a ? over where this high level came from. All other ICP pollutants are at undetectable levels.

I have checked everything with a fine tooth comb. All equipment is just under a year old.

2x Jebao 15000 lp/h return pumps. Inspected and no signs of any corrosion.
1x Reef Octopus Skimmer Varios 8. Inspected and no signs of any corrosion.
2x Schego Heaters. No sign of any corrosion even under the caps.
2x MP40's All fully taken apart and look perfect.

Thoroughly searched the tank and sump for any rusting hinges / screws / brackets etc. The only metal I found was a jubilee clip well above the water with zero corrosion but removed it anyway. This clearly wasn't the issue as the next test came back with higher zinc levels again. I have no screen top.

ICP results:

Aluminium:

10/10/18 = 11.5 ug/l
11/12/18 = 122 ug/l !!
30/1/19 = 55 ug/l !

Zinc:

10/10/18 = 9.32 ug/l
11/12/18 = 52.29 ug/l !!

30% Water change + Added Cuprisorb

30/1/19 = 70.89 ug/l !!!

Continued Cuprisorb + added external canister filter @ 1400 lp/h full of Polyfilter media that I have been keeping an eye on and renewing.

During this time I have been adding SPS, which strangely have been doing fine and all 10 frags show signs of growth and decent polyp extension. The LPS and Zoas are a different story. They have been around 50% of the size they normally were before these issues and have been closing fully up randomly during the day.

I was about to do another 30% water change in the next few days before another ICP in a couple weeks but this takes a bit of planning and time when you are making nearly 100 gallons. RODI machine on for around 12-14 hours and a big container in the living room which the wife loves :D

I was searching about similar problems that others have had and there has been a suggestion that certain salt can have elevated levels of pollutants and I came across these tests. This was posted on April 2017 and so may not be relevant to the current production methods or batches but...

https://reefhub.pl/test-of-marine-salts/

io.JPG


Guess which salt has one of the highest if not the highest Aluminum and Zinc? Yes, Instant Ocean.

Zn = 126.66 ug/l !!!
Al = 9.81 ug/l

Clearly, I'm going to get different salt before a water change but Instant Ocean seems to be fairly popular and so you'd expect everyone to have the same problems?

Thoughts?
Are you using Bio Pellets ? Or anything else that is White ?
 

Tikki

Active Member
View Badges
Joined
Jul 8, 2025
Messages
158
Reaction score
142
Location
Pensacola
Rating - 0%
0   0   0
I have been fighting high zinc levels for the last few months and didn't even consider the salt that I had changed to (Instant Ocean) over that period might be to be to blame. I'm more concerned about the Zinc at this time as Aluminium has come down although there is a ? over where this high level came from. All other ICP pollutants are at undetectable levels.

I have checked everything with a fine tooth comb. All equipment is just under a year old.

2x Jebao 15000 lp/h return pumps. Inspected and no signs of any corrosion.
1x Reef Octopus Skimmer Varios 8. Inspected and no signs of any corrosion.
2x Schego Heaters. No sign of any corrosion even under the caps.
2x MP40's All fully taken apart and look perfect.

Thoroughly searched the tank and sump for any rusting hinges / screws / brackets etc. The only metal I found was a jubilee clip well above the water with zero corrosion but removed it anyway. This clearly wasn't the issue as the next test came back with higher zinc levels again. I have no screen top.

ICP results:

Aluminium:

10/10/18 = 11.5 ug/l
11/12/18 = 122 ug/l !!
30/1/19 = 55 ug/l !

Zinc:

10/10/18 = 9.32 ug/l
11/12/18 = 52.29 ug/l !!

30% Water change + Added Cuprisorb

30/1/19 = 70.89 ug/l !!!

Continued Cuprisorb + added external canister filter @ 1400 lp/h full of Polyfilter media that I have been keeping an eye on and renewing.

During this time I have been adding SPS, which strangely have been doing fine and all 10 frags show signs of growth and decent polyp extension. The LPS and Zoas are a different story. They have been around 50% of the size they normally were before these issues and have been closing fully up randomly during the day.

I was about to do another 30% water change in the next few days before another ICP in a couple weeks but this takes a bit of planning and time when you are making nearly 100 gallons. RODI machine on for around 12-14 hours and a big container in the living room which the wife loves :D

I was searching about similar problems that others have had and there has been a suggestion that certain salt can have elevated levels of pollutants and I came across these tests. This was posted on April 2017 and so may not be relevant to the current production methods or batches but...

https://reefhub.pl/test-of-marine-salts/

io.JPG


Guess which salt has one of the highest if not the highest Aluminum and Zinc? Yes, Instant Ocean.

Zn = 126.66 ug/l !!!
Al = 9.81 ug/l

Clearly, I'm going to get different salt before a water change but Instant Ocean seems to be fairly popular and so you'd expect everyone to have the same problems?

Thoughts?
Are you using Bio Pellets ? Or anything else that is White ?
I’m sorry, I have probably confused things by commenting on an old thread. If that question is meant for me, I don’t use any bio pellets or anything in a reactor. I have max spec bio ball’s and some black plastic bio ball’s from brs.
 

Tikki

Active Member
View Badges
Joined
Jul 8, 2025
Messages
158
Reaction score
142
Location
Pensacola
Rating - 0%
0   0   0
I have been fighting high zinc levels for the last few months and didn't even consider the salt that I had changed to (Instant Ocean) over that period might be to be to blame. I'm more concerned about the Zinc at this time as Aluminium has come down although there is a ? over where this high level came from. All other ICP pollutants are at undetectable levels.

I have checked everything with a fine tooth comb. All equipment is just under a year old.

2x Jebao 15000 lp/h return pumps. Inspected and no signs of any corrosion.
1x Reef Octopus Skimmer Varios 8. Inspected and no signs of any corrosion.
2x Schego Heaters. No sign of any corrosion even under the caps.
2x MP40's All fully taken apart and look perfect.

Thoroughly searched the tank and sump for any rusting hinges / screws / brackets etc. The only metal I found was a jubilee clip well above the water with zero corrosion but removed it anyway. This clearly wasn't the issue as the next test came back with higher zinc levels again. I have no screen top.

ICP results:

Aluminium:

10/10/18 = 11.5 ug/l
11/12/18 = 122 ug/l !!
30/1/19 = 55 ug/l !

Zinc:

10/10/18 = 9.32 ug/l
11/12/18 = 52.29 ug/l !!

30% Water change + Added Cuprisorb

30/1/19 = 70.89 ug/l !!!

Continued Cuprisorb + added external canister filter @ 1400 lp/h full of Polyfilter media that I have been keeping an eye on and renewing.

During this time I have been adding SPS, which strangely have been doing fine and all 10 frags show signs of growth and decent polyp extension. The LPS and Zoas are a different story. They have been around 50% of the size they normally were before these issues and have been closing fully up randomly during the day.

I was about to do another 30% water change in the next few days before another ICP in a couple weeks but this takes a bit of planning and time when you are making nearly 100 gallons. RODI machine on for around 12-14 hours and a big container in the living room which the wife loves :D

I was searching about similar problems that others have had and there has been a suggestion that certain salt can have elevated levels of pollutants and I came across these tests. This was posted on April 2017 and so may not be relevant to the current production methods or batches but...

https://reefhub.pl/test-of-marine-salts/

io.JPG


Guess which salt has one of the highest if not the highest Aluminum and Zinc? Yes, Instant Ocean.

Zn = 126.66 ug/l !!!
Al = 9.81 ug/l

Clearly, I'm going to get different salt before a water change but Instant Ocean seems to be fairly popular and so you'd expect everyone to have the same problems?

Thoughts?
Are you using Bio Pellets ? Or anything else that is White ?
I’m sorry, I have probably confused things by commenting on an old thread. If that question is meant for me, I don’t use any bio pellets or anything in a reactor. I have max spec bio ball’s and some black plastic bio ball’s from brs.
I removed a little bag of ceramic bio beads from the sump a few days ago
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
89,263
Reaction score
92,306
Location
Massachusetts, United States
Rating - 0%
0   0   0
Thanks. Here's my timeline. I'll follow up with some photos of the tank. I use instant ocean reef crystals and do weekly 20% water changes. I use AFR on a dosing pump.


The zinc timeline (µg/L)

  • Mid-August (ATI ICP): Aquarium Zn 0.57 (aluminum ~4 µg/L). RO Zn 0
  • September (ATI ICP): Aquarium Zn 69.43 and RO Zn 10.45.
    • Biggest change between August and September: we added a 3-stage whole-house filter because our city water looked visibly contaminated. Stages were sediment → KDF → carbon (ACB). We also installed fresh SED/GAC/ACB/DI on the RO/DI around that time.
    • Ran CupriSorb in a bag in the sump for 7-10 days
    • Cleaned out mixing bucket
  • October (Triton ICP): Aquarium Zn 4.0 (!). No RO sample submitted with Triton.
  • November (ATI ICP): Aquarium Zn 90.89 and RO Zn 1.24
Since then, we’ve:
  • Ran Metasorb and CupriSorb for about a week each
  • Removed the KDF in whole house filter completely and replaced it with a second ACB
  • Removed one small ceramic bead bag from the sump.
  • Removed an old Hydor Koralia from the refugium.
  • Replaced heater with dual BRS titanium tubes.

Questions:

  • If these zinc levels are at all true, should I expect to see things obviously suffering? We have acros, a clam, shrimp, clean up crew, mixed corals.
  • Even if RO level was 10ug/L, I don’t understand how the tank jumped from 0 to 69 that quickly unless the RO/whole-house situation was briefly much worse than what we sampled, or there’s another source. By November ATI says RO is low (~1.2), but the tank is higher (~90).
  • Is there some reason why the ATI test would come in artificially high, or the Triton artificially low? It's hard to imagine the zinc has swung that much. I have a bottle of detox, but I have not ever used it
  • I have been growing Phytoplankton in this RO water very successfully since early November. Would the zinc levels we're seeing in the RO affect that?
  • I have two ATI tests in hand. I'm preparing to sample this week. Should I send one off from my mixing bucket? What if I took the "RO" sample portion that's included with one of the tests from the mixing bucket instead, or would that not work because it's salty?
In general, there’s not especially good general info on which levels of which trace elements cause which apparent problems when elevated.

So aquarium zinc is currently 90 ug/L?

Are there visible coral problems?

Is the ro/di always 0 ppm tds?
 

TOP 10 Trending Threads

WHAT AMOUNT OF LIVE ROCK AND SAND SHOULD BE PRIORITIZED FOR OPTIMAL BIODIVERSITY/FILTRATION?

  • 100% live rock + bagged sand

    Votes: 37 27.2%
  • 100% dry rock + 100% live sand

    Votes: 46 33.8%
  • 50/50 live/dry rock, 50/50 live/bagged sand

    Votes: 30 22.1%
  • 75% live rock, 25% live sand

    Votes: 13 9.6%
  • 25% live rock, 75% live sand

    Votes: 10 7.4%
Back
Top