ICP test high Zinc. (38ug/l)

[vlad2spinn]

I just received me ICP test results. Everything is OK, or close, except very high zinc (38 ug/l), copper slightly high at (6.271 ug/l. I have 2 possible known zinc sources:

1) I use 100% rainwater collected from my roof in my tank after running it through RODI. Sometime back I noticed that the galvanized pump intake strainer had a lot of corrosion, so I replaced with stainless steel, but the original strainer was in use for 6-8 month before I noticed. It is possible my DI resin is depleted but I have not been concerned since rainwater fed to RODI averages 35-50 microS/cm (22-32 TDS), after membrane is about 5 microS/cm (3 TDS), and after DI 0.05 micoS/cm (0.03 TDS). So I don’t know if zinc contamination of the rainwater would make it through the RODI.

2) I dropped a pair of tweezers and forgot about them, once I remembered and got them out, they were quite corroded. My system is about 1400 gallons total system volume so not sure if this would explain such high level.

Since both sources have been eliminated, I will wait to see if future ICP tests show increased or decreased zinc level. If it continues to go up, I will have to locate alternate zinc source. In the mean time I need to try to reduce current zinc level:

1) Are there any known methods of reducing zinc without major water changes? Triton recommends 6-15% water changes. For my system that is 225 gallon water changes x 6. I currently do about 40 gallons/week when I backwash my sand filter (60-80 gallons of rainwater to backwash and 40 gallons of tank water to rinse)

2) What would be considered safe zinc level for acropora? I experienced tank crash due to low nutrients and dino outbreak about 6 month ago and lost most SPS. I beat dinos, and redesigned my filtration to increase nutrient levels. Tank has been stable and looking good for couple of months. Currently just LPS, montiporas, pocillopora, and stylophora (what survived the crash). Even with high zinc Montipora are growing well, pocillopora and stylophora have good polip extensions but slow growth so far. I bought a lot of acros, and have them in QT now. I was going to add them, but now knowing that tank has high zinc I am hesitant. Would it be ok to add some to the tank? Or is it likely they will die with high zinc levels?

I will send a sample of my QT/frag tank water for ICP testing. If this also shows high zinc, then most likely source is my RODI (depleted DI resin). Till then I do not want to do major water changes, if there is a chance RODI water is the source of zinc.

 

[Xanka]

Here also high levels of zinc. No idea where it comes from and how to lower it. Any advice is welcome.

//lab.atiaquaristik.com/share/2f58afbbc371139ac106

 

[Randy Holmes-Farley]

Zinc will typically come from metals arts on or near the water, or overdosing of an additive. The tweezers could have been the source.

I don't think folks have identified either the minimum required for most trace elements, or exactly how much is too much. It's very complicated as it very often depends on the chemical form present, including how the metal may be bound to organic matter.

I'd personally search for metal things before doing anything else. Hose clamps, screws, etc.

Zinc in 0.03 uS/cm RO/DI is not likely the source. But if the DI depleted and you didn't notice, it could well be from your collection description. What are you using to measure 0.03 uS/cm? Be sure it is not 0.03 mS/cm (30 uS/cm).

 

[Joedubyk]

I am a roofer and the asphalt shingles have zinc in them now to get rid of algae/mold etc. That's likely where your zinc is originating from.

 

[Joedubyk]

Zinc will typically come from metals arts on or near the water, or overdosing of an additive. The tweezers could have been the source.

I don't think folks have identified either the minimum required for most trace elements, or exactly how much is too much. It's very complicated as it very often depends on the chemical form present, including how the metal may be bound to organic matter.

I'd personally search for metal things before doing anything else. Hose clamps, screws, etc.

Zinc in 0.03 uS/cm RO/DI is not likely the source. But if the DI depleted and you didn't notice, it could well be from your collection description. What are you using to measure 0.03 uS/cm? Be sure it is not 0.03 mS/cm (30 uS/cm).

They put zinc in shingles. As the rain water hits the zinc it runs down the roof, it prevents mold from growing on it. Id bet money that's his source

 

[Randy Holmes-Farley]

They put zinc in shingles. As the rain water hits the zinc it runs down the roof, it prevents mold from growing on it. Id bet money that's his source

But he then passes it through his RO/DI and gets (reportedly) way below 1 ppm TDS.

i do agree that the raw rainwater could be a big source. Corroded galvanized would be a huge source too.

 

[Xanka]

Can activated carbon absorb zinc? Or how can you lower it?

 

[vlad2spinn]

Zinc will typically come from metals arts on or near the water, or overdosing of an additive. The tweezers could have been the source.

I don't think folks have identified either the minimum required for most trace elements, or exactly how much is too much. It's very complicated as it very often depends on the chemical form present, including how the metal may be bound to organic matter.

I'd personally search for metal things before doing anything else. Hose clamps, screws, etc.

Zinc in 0.03 uS/cm RO/DI is not likely the source. But if the DI depleted and you didn't notice, it could well be from your collection description. What are you using to measure 0.03 uS/cm? Be sure it is not 0.03 mS/cm (30 uS/cm).

I built my own RODI and controller that runs it, so error on my part is possible. I use +GF+ Signet 2850 Conductivity Sensor (0.01 cell) that has a span of 0-100 uS. My PLC controller scales the 4-20mA signal generated by the sensor to reed the results. I will double check my programing to make sure I am scaling correctly. I think I have a spare probe I can use and compare the results and make sure the probe is calibrated correctly.

During my search I only found one study that talked about 62% growth reduction and loss of chlorophyll-a in stylophora pistillata with zinc concentrations of 100ug/l, but no data published on zinc concentrations between 10-99ug/l

 

[vlad2spinn]

They put zinc in shingles. As the rain water hits the zinc it runs down the roof, it prevents mold from growing on it. Id bet money that's his source

I have metal (aluminum) roof so that is not the zinc source for me, unless they add zinc to aluminum or to the paint that is applied to aluminum at the factory. I was concerned about high aluminum contamination but that is not issue for me. My aluminum reading is only 10 ug/l.

 

[Randy Holmes-Farley]

I'm not sure this level is a problem, but it may be bound by metal-binding polymers such as metasorb, cuprisorb, and poly filter.

Some may bind to GAC, but perhaps mostly because GAC is binding organics that then bind tot eh GAC.

 

[Joedubyk]

I have metal (aluminum) roof so that is not the zinc source for me, unless they add zinc to aluminum or to the paint that is applied to aluminum at the factory. I was concerned about high aluminum contamination but that is not issue for me. My aluminum reading is only 10 ug/l.

It could be a galvalume roof which does have zinc on it (im a metal roofer). The paint is usually a kynar finish. i doubt it leeches anything though.

 

[vlad2spinn]

It could be a galvalume roof which does have zinc on it (im a metal roofer). The paint is usually a kynar finish. i doubt it leeches anything though.

I built my house and installed the roof. I bought coils of aluminum from Englert and had a roofing company rool the panels for me onsite, so I am certain it is aluminum. It does have Kynar 500 finish

 

[vlad2spinn]

But he then passes it through his RO/DI and gets (reportedly) way below 1 ppm TDS.

i do agree that the raw rainwater could be a big source. Corroded galvanized would be a huge source too.

I just checked my RODI water with standard hobby grade TDS meter and it read zero. I have not verified yet that 0.03 uS/cm reading is correct, but at this point I think DI resin is OK.

 

[Randy Holmes-Farley]

I just checked my RODI water with standard hobby grade TDS meter and it read zero. I have not verified yet that 0.03 uS/cm reading is correct, but at this point I think DI resin is OK.

Sounds reasonable.

 

[RomanFarley]

Sounds reasonable.

Hi @Randy Holmes-Farley , the sea water I collect myself and use ranges between 14 - 77 ug/l in Zinc (results from ICP tests). However, I have been using it for a couple of years and all corals in the tank are fine. Would you personally be concerned by these levels yourself?

You mentioned "it very often depends on the chemical form present, including how the metal may be bound to organic matter." What do you exactly mean by that?

Could it be that zinc found in sea water is bound to organics and therefore is completely safe? Therefore when an ICP places those zinc levels in a warning range, that it is not actually an issue?

 

[Courtney Aldrich]

I just received me ICP test results. Everything is OK, or close, except very high zinc (38 ug/l), copper slightly high at (6.271 ug/l. I have 2 possible known zinc sources:

1) I use 100% rainwater collected from my roof in my tank after running it through RODI. Sometime back I noticed that the galvanized pump intake strainer had a lot of corrosion, so I replaced with stainless steel, but the original strainer was in use for 6-8 month before I noticed. It is possible my DI resin is depleted but I have not been concerned since rainwater fed to RODI averages 35-50 microS/cm (22-32 TDS), after membrane is about 5 microS/cm (3 TDS), and after DI 0.05 micoS/cm (0.03 TDS). So I don’t know if zinc contamination of the rainwater would make it through the RODI.

2) I dropped a pair of tweezers and forgot about them, once I remembered and got them out, they were quite corroded. My system is about 1400 gallons total system volume so not sure if this would explain such high level.

Since both sources have been eliminated, I will wait to see if future ICP tests show increased or decreased zinc level. If it continues to go up, I will have to locate alternate zinc source. In the mean time I need to try to reduce current zinc level:

1) Are there any known methods of reducing zinc without major water changes? Triton recommends 6-15% water changes. For my system that is 225 gallon water changes x 6. I currently do about 40 gallons/week when I backwash my sand filter (60-80 gallons of rainwater to backwash and 40 gallons of tank water to rinse)

2) What would be considered safe zinc level for acropora? I experienced tank crash due to low nutrients and dino outbreak about 6 month ago and lost most SPS. I beat dinos, and redesigned my filtration to increase nutrient levels. Tank has been stable and looking good for couple of months. Currently just LPS, montiporas, pocillopora, and stylophora (what survived the crash). Even with high zinc Montipora are growing well, pocillopora and stylophora have good polip extensions but slow growth so far. I bought a lot of acros, and have them in QT now. I was going to add them, but now knowing that tank has high zinc I am hesitant. Would it be ok to add some to the tank? Or is it likely they will die with high zinc levels?

I will send a sample of my QT/frag tank water for ICP testing. If this also shows high zinc, then most likely source is my RODI (depleted DI resin). Till then I do not want to do major water changes, if there is a chance RODI water is the source of zinc.

I just received me ICP test results. Everything is OK, or close, except very high zinc (38 ug/l), copper slightly high at (6.271 ug/l. I have 2 possible known zinc sources:

1) I use 100% rainwater collected from my roof in my tank after running it through RODI. Sometime back I noticed that the galvanized pump intake strainer had a lot of corrosion, so I replaced with stainless steel, but the original strainer was in use for 6-8 month before I noticed. It is possible my DI resin is depleted but I have not been concerned since rainwater fed to RODI averages 35-50 microS/cm (22-32 TDS), after membrane is about 5 microS/cm (3 TDS), and after DI 0.05 micoS/cm (0.03 TDS). So I don’t know if zinc contamination of the rainwater would make it through the RODI.

2) I dropped a pair of tweezers and forgot about them, once I remembered and got them out, they were quite corroded. My system is about 1400 gallons total system volume so not sure if this would explain such high level.

Since both sources have been eliminated, I will wait to see if future ICP tests show increased or decreased zinc level. If it continues to go up, I will have to locate alternate zinc source. In the mean time I need to try to reduce current zinc level:

1) Are there any known methods of reducing zinc without major water changes? Triton recommends 6-15% water changes. For my system that is 225 gallon water changes x 6. I currently do about 40 gallons/week when I backwash my sand filter (60-80 gallons of rainwater to backwash and 40 gallons of tank water to rinse)

2) What would be considered safe zinc level for acropora? I experienced tank crash due to low nutrients and dino outbreak about 6 month ago and lost most SPS. I beat dinos, and redesigned my filtration to increase nutrient levels. Tank has been stable and looking good for couple of months. Currently just LPS, montiporas, pocillopora, and stylophora (what survived the crash). Even with high zinc Montipora are growing well, pocillopora and stylophora have good polip extensions but slow growth so far. I bought a lot of acros, and have them in QT now. I was going to add them, but now knowing that tank has high zinc I am hesitant. Would it be ok to add some to the tank? Or is it likely they will die with high zinc levels?

I will send a sample of my QT/frag tank water for ICP testing. If this also shows high zinc, then most likely source is my RODI (depleted DI resin). Till then I do not want to do major water changes, if there is a chance RODI water is the source of zinc.

You can use Cuprisorb (https://www.bulkreefsupply.com/cuprisorb-copper-remover-resin-seachem.html) to remove both copper and zinc. This inexpensive resin selectively binds heavy metals and favors copper over all other metals, but likely will also selectively bind zinc. Although the resin is proprietary it likely uses the well known imidodiacetic acid chelating group, which is manufactured by many companies such as Dupont for wastewater cleanup. I've attached an old paper showing zinc is efficiency removed (99%) by the resin.

 

[Randy Holmes-Farley]

Hi @Randy Holmes-Farley , the sea water I collect myself and use ranges between 14 - 77 ug/l in Zinc (results from ICP tests). However, I have been using it for a couple of years and all corals in the tank are fine. Would you personally be concerned by these levels yourself?

You mentioned "it very often depends on the chemical form present, including how the metal may be bound to organic matter." What do you exactly mean by that?

Could it be that zinc found in sea water is bound to organics and therefore is completely safe? Therefore when an ICP places those zinc levels in a warning range, that it is not actually an issue?

I do not know what levels actually constitute a problem, but your levels are higher than typical for unpolluted surface seawater. Natural values might be more like 0.5 ug/L.

How do you collect it?

 

[SPS2020]

Just saw this thread and I have high levels of Zinc (ICP 14.00 µg/l). It was suggested (and highly probable) that the Zinc could come from lotions\creams\ointments on the hands. Knock on wood, I have not noticed any adverse reactions to any Acropora (dominant) in my tank.

 

[chipchipbro]

Ive heard from some people in my group they have had high zinc in the tanks due to frozen mysis soaked up with liquid garlic.. and indeed they stopped that and zinc levels were better after..

 

[Icryhard]

Ive heard from some people in my group they have had high zinc in the tanks due to frozen mysis soaked up with liquid garlic.. and indeed they stopped that and zinc levels were better after..

That would be REALLY unlucky on my part. I’ve fed a lot of mysis/garlic mix and I’m at 120 zinc… does this only happen when this particular mix is ongoing, or also when feeding frozen mysis (without garlic)