ATI ICP Test solutions are in. Any suggestions

[SifuMemphis]

Got my ATI ICP test back, and shows lows iodine, which I have resolved by dosing some over a couple days. I am still pretty stumped on the Tin:

RODI water:

From my RODI water, shows 8.29 UG/L. I switched out everything on my RODI unit about 2-3 months prior to this test (except the membrane). I looked for any hinges, screws, rust, etc, and nothing seems to be the culprit for the 8.29 number. My RO water container which I fill up that my tank pulls from is a Innovative Marine AUQA Gadget HydroFill Ti Auto Top Off ATO Reservoir - 15 Gallon, which could MAYBE be leaching Tin from glass (Heard float glass can leach tin) -- but I had this unit for about a year so far. I checked the Apex pump in the reservoir, and found no rust on it either.

My Tank results:

My tank results show Tin, but at a lower level at 5.74 ug/l. The only thing I can find in my sump, is a screw that was rusted that was holding up my UV light. I replaced the screw with SS screws, but i doubt this was the cause for the Tin in the tank.

My assumption is, when the ATO unit is putting RODI water back into the tank, it's slowly adding Tin into it (since it was 8.74 in the test). Am I missing something? Where could the Tin be coming from? Should I replace my Membrane in the RODI unit? It's been about 2 years, but still showing 0 TDS. Currently my pressure on the unit is 60 PSI. This was the minimum required, so I ordered a booster to get it upt to 80 psi. This might help with better filtration in removing Tin?

Any help / thoughts would be great.

@Randy Holmes-Farley

 

[PBar]

Agree, Tin is probably coming from process of “RO water” and not very likely from anywhere else in the tank.
The question is where in that process... rusty from the tap where you connect the RO?
On the other hand, in my option, this level is not an issue...

 

[MnFish1]

Got my ATI ICP test back, and shows lows iodine, which I have resolved by dosing some over a couple days. I am still pretty stumped on the Tin:

RODI water:

From my RODI water, shows 8.29 UG/L. I switched out everything on my RODI unit about 2-3 months prior to this test (except the membrane). I looked for any hinges, screws, rust, etc, and nothing seems to be the culprit for the 8.29 number. My RO water container which I fill up that my tank pulls from is a Innovative Marine AUQA Gadget HydroFill Ti Auto Top Off ATO Reservoir - 15 Gallon, which could MAYBE be leaching Tin from glass (Heard float glass can leach tin) -- but I had this unit for about a year so far. I checked the Apex pump in the reservoir, and found no rust on it either.

My Tank results:

My tank results show Tin, but at a lower level at 5.74 ug/l. The only thing I can find in my sump, is a screw that was rusted that was holding up my UV light. I replaced the screw with SS screws, but i doubt this was the cause for the Tin in the tank.

My assumption is, when the ATO unit is putting RODI water back into the tank, it's slowly adding Tin into it (since it was 8.74 in the test). Am I missing something? Where could the Tin be coming from? Should I replace my Membrane in the RODI unit? It's been about 2 years, but still showing 0 TDS. Currently my pressure on the unit is 60 PSI. This was the minimum required, so I ordered a booster to get it upt to 80 psi. This might help with better filtration in removing Tin?

Any help / thoughts would be great.

@Randy Holmes-Farley

Forget the test for a second. What problems are you having with your tank? If any? If I am reading 'correctly' - the 'tin' in your RODI is higher than in your tank - which doesn't make sense - if you are using that RODI water to top off your tank (unless something in your tank is using up tin). In any case - according to a couple sources - the concentration of tin in seawater is between 3 and 10 ppb - so neither of your results seems in any way 'alarming'. Realize that certain algae take up tin. Mussels for example can contain 150 ppb tin. If your tank has no problems - I would ignore the levels. And if your tank is having problems - I would suggest that perhaps tin is not the issue causing them.

 

[Randy Holmes-Farley]

Tin seems to commonly come from plastics such as PVC. Might be the holding container, etc. The tin value in the tank does not appear to be high enough to be a problem based on the fact that many folks have that level without apparent issue. But the chemical form of tin matters a lot and is likely to vary from tank to tank.

What did you dose for iodine?
I'd be interested to see if there is an apparent effect of the iodine as I do not consider it useful in most tanks.

 

[Courtney Aldrich]

I am no expert on water chemistry, but spent a little time researching for you. Tin is likely present as an organotin compound (dibutyltin or tributyl tin). These compounds are very toxic to marine life and invertebrates can be affected by levels as low as 0.001 ug/L (0.001 ppb). I have attached a book on heavy metal environmental toxins (Chapter 2 is on Organotins compounds). I also found some information on organotin levels in PVC pipe. The PVC Pipe Association in the US says that there are less than 4 ppb (0.004 ug/L) allowed (see attached document), so I don't think leaching from the small surface area of PVC could lead to equivalent levels in a volume of several hundred liters. Organotin compounds are used in paints and fungicides too, so this could be another source. I don't believe metallic tin is typically used in metal screws/nuts, but tin is a critical component of solder helping to lower the melting point and is also a component of bronze (~90% copper and about 10% tin). Lastly, the findings that your tin levels are slightly lower in your tank than in your RO/DI system is not surprising since macroalgae and likely other organisms (clams, corals, etc..) have been shown to remove tin from saltwater (see: https://www.witpress.com/Secure/elibrary/papers/WP03/WP03025FU.pdf)

 

[Randy Holmes-Farley]

I am no expert on water chemistry, but spent a little time researching for you. Tin is likely present as an organotin compound (dibutyltin or tributyl tin). These compounds are very toxic to marine life and invertebrates can be affected by levels as low as 0.001 ug/L (0.001 ppb). I have attached a book on heavy metal environmental toxins (Chapter 2 is on Organotins compounds). I also found some information on organotin levels in PVC pipe. The PVC Pipe Association in the US says that there are less than 4 ppb (0.004 ug/L) allowed (see attached document), so I don't think leaching from the small surface area of PVC could lead to equivalent levels in a volume of several hundred liters. Organotin compounds are used in paints and fungicides too, so this could be another source. I don't believe metallic tin is typically used in metal screws/nuts, but tin is a critical component of solder helping to lower the melting point and is also a component of bronze (~90% copper and about 10% tin). Lastly, the findings that your tin levels are slightly lower in your tank than in your RO/DI system is not surprising since macroalgae and likely other organisms (clams, corals, etc..) have been shown to remove tin from saltwater (see: https://www.witpress.com/Secure/elibrary/papers/WP03/WP03025FU.pdf)

I have to disagree with some of these points, but most importantly, we have seen tin results for hundreds of reef tanks. Those showing levels like that here (less than 10 ug/L) do not generally display any apparent problems. Some tanks have more than 100 ug/L without showing apparent issue.

There are many possible tin compounds used in plastics (a simple search on suppliers of tin for plastics shows lots of them), and we also cannot assume the forms percent in the tank water are unchanged from the original forms.

The amount present in some plastics is incredibly higher than 4 ppb. Like whole number percentages:

Polyvinyl chloride - Wikipedia

en.wikipedia.org

"Tin mercaptides are widely used globally in rigid PVC applications due to their high efficiency and proven performance. Typical usage levels are 0.3 (pipe) to 2.5 phr (foam) depending on the application. "

 

[Courtney Aldrich]

I have to disagree with some of these points, but most importantly, we have seen tin results for hundreds of reef tanks. Those showing levels like that here (less than 10 ug/L) do not generally display any apparent problems. Some tanks have more than 100 ug/L without showing apparent issue.

There are many possible tin compounds used in plastics (a simple search on suppliers of tin for plastics shows lots of them), and we also cannot assume the forms percent in the tank water are unchanged from the original forms.

The amount present in some plastics is incredibly higher than 4 ppb. Like whole number percentages:

Polyvinyl chloride - Wikipedia

en.wikipedia.org

"Tin mercaptides are widely used globally in rigid PVC applications due to their high efficiency and proven performance. Typical usage levels are 0.3 (pipe) to 2.5 phr (foam) depending on the application. "

Hi Randy, Thanks for critical feedback. I have tried to respond to your comments point-by-point.

1. "I have to disagree with some of these points, but most importantly, we have seen tin results for hundreds of reef tanks. Those showing levels like that here (less than 10 ug/L) do not generally display any apparent problems. Some tanks have more than 100 ug/L without showing apparent issue."

Response: Tin is extremely toxic to marine life as noted in the dozens of scientific studies cited in the chapter I previously attached on the environmental toxicity of tin. Organotin pollutants have been shown to affect growth of some invertebrates at levels as low as 1 ppb. This does not mean 1 ppb is toxic to all marine life. I carefully stated "tin is very toxic to marine life and invertebrates can be affected by levels as low as 0.001 ug/L (0.001 ppb)." I don't think you can refute this statement. I would agree that the statement tin is extremely toxic is relative and also cannot refute your experiences that some people have experienced no affect with 100 ppb. I would counter that anything that has potential toxicity in the parts per billion Is pretty dang toxic.

2. "There are many possible tin compounds used in plastics (a simple search on suppliers of tin for plastics shows lots of them)"

Response: I only commented on the leachable tin levels in PVC since this type of plastic was mentioned earlier in the thread as potentially a source of tin. The data sheet I provided, entitled "Organotin(tin() Stabilizers: Not a Health Concern for PVC Pipe" from the PVC Pipe Association in the United States (https://www.uni-bell.org) stated that the 'total of any potentially leachable amounts of tin from OPVC pipe is less than 4 ppb' by NSF Standard 61. I agree that other types of plastic and manufacturers outside the US in Europe and Asia may not conform to the US Standards.

3. "and we also cannot assume the forms percent in the tank water are unchanged from the original forms."

Response: Your point that the "forms percent in the tank water are unchanged from the original forms" is absolutely valid. However, I said " leaching from the small surface area of PVC could lead to equivalent levels in a volume of several hundred liters". I did not intend to say that the molecular form of tin was equivalent, but that by the simple principles of mass conservation that the concentration of tin present in a small PVC pipe cannot lead to higher concentration in a larger volume of water.

4. "The amount present in some plastics is incredibly higher than 4 ppb. Like whole number percentages:

Polyvinyl chloride - Wikipedia

en.wikipedia.org

"Tin mercaptides are widely used globally in rigid PVC applications due to their high efficiency and proven performance. Typical usage levels are 0.3 (pipe) to 2.5 phr (foam) depending on the application. "

Response: I did incorrectly state that the amount of tin present in PVC was in the ppb range, but after careful reading see the document was referring to the amount of 'leachable tin'. You are correct, PVC contains a lot tin!

 

[Randy Holmes-Farley]

Hi Randy, Thanks for critical feedback. I have tried to respond to your comments point-by-point.

1. "I have to disagree with some of these points, but most importantly, we have seen tin results for hundreds of reef tanks. Those showing levels like that here (less than 10 ug/L) do not generally display any apparent problems. Some tanks have more than 100 ug/L without showing apparent issue."

Response: Tin is extremely toxic to marine life as noted in the dozens of scientific studies cited in the chapter I previously attached on the environmental toxicity of tin. Organotin pollutants have been shown to affect growth of some invertebrates at levels as low as 1 ppb. This does not mean 1 ppb is toxic to all marine life. I carefully stated "tin is very toxic to marine life and invertebrates can be affected by levels as low as 0.001 ug/L (0.001 ppb)." I don't think you can refute this statement. I would agree that the statement tin is extremely toxic is relative and also cannot refute your experiences that some people have experienced no affect with 100 ppb. I would counter that anything that has potential toxicity in the parts per billion Is pretty dang toxic.

2. "There are many possible tin compounds used in plastics (a simple search on suppliers of tin for plastics shows lots of them)"

Response: I only commented on the leachable tin levels in PVC since this type of plastic was mentioned earlier in the thread as potentially a source of tin. The data sheet I provided, entitled "Organotin(tin() Stabilizers: Not a Health Concern for PVC Pipe" from the PVC Pipe Association in the United States (https://www.uni-bell.org) stated that the 'total of any potentially leachable amounts of tin from OPVC pipe is less than 4 ppb' by NSF Standard 61. I agree that other types of plastic and manufacturers outside the US in Europe and Asia may not conform to the US Standards.

3. "and we also cannot assume the forms percent in the tank water are unchanged from the original forms."

Response: Your point that the "forms percent in the tank water are unchanged from the original forms" is absolutely valid. However, I said " leaching from the small surface area of PVC could lead to equivalent levels in a volume of several hundred liters". I did not intend to say that the molecular form of tin was equivalent, but that by the simple principles of mass conservation that the concentration of tin present in a small PVC pipe cannot lead to higher concentration in a larger volume of water.

4. "The amount present in some plastics is incredibly higher than 4 ppb. Like whole number percentages:

Polyvinyl chloride - Wikipedia

en.wikipedia.org

"Tin mercaptides are widely used globally in rigid PVC applications due to their high efficiency and proven performance. Typical usage levels are 0.3 (pipe) to 2.5 phr (foam) depending on the application. "

Response: I did incorrectly state that the amount of tin present in PVC was in the ppb range, but after careful reading see the document was referring to the amount of 'leachable tin'. You are correct, PVC contains a lot tin!

I'll just add that not all PVC we use is NSF approved. Lots of parts and fittings appear to not be.

 

[MnFish1]

Hi Randy, Thanks for critical feedback. I have tried to respond to your comments point-by-point.

1. "I have to disagree with some of these points, but most importantly, we have seen tin results for hundreds of reef tanks. Those showing levels like that here (less than 10 ug/L) do not generally display any apparent problems. Some tanks have more than 100 ug/L without showing apparent issue."

Response: Tin is extremely toxic to marine life as noted in the dozens of scientific studies cited in the chapter I previously attached on the environmental toxicity of tin. Organotin pollutants have been shown to affect growth of some invertebrates at levels as low as 1 ppb. This does not mean 1 ppb is toxic to all marine life. I carefully stated "tin is very toxic to marine life and invertebrates can be affected by levels as low as 0.001 ug/L (0.001 ppb)." I don't think you can refute this statement. I would agree that the statement tin is extremely toxic is relative and also cannot refute your experiences that some people have experienced no affect with 100 ppb. I would counter that anything that has potential toxicity in the parts per billion Is pretty dang toxic.

2. "There are many possible tin compounds used in plastics (a simple search on suppliers of tin for plastics shows lots of them)"

Response: I only commented on the leachable tin levels in PVC since this type of plastic was mentioned earlier in the thread as potentially a source of tin. The data sheet I provided, entitled "Organotin(tin() Stabilizers: Not a Health Concern for PVC Pipe" from the PVC Pipe Association in the United States (https://www.uni-bell.org) stated that the 'total of any potentially leachable amounts of tin from OPVC pipe is less than 4 ppb' by NSF Standard 61. I agree that other types of plastic and manufacturers outside the US in Europe and Asia may not conform to the US Standards.

3. "and we also cannot assume the forms percent in the tank water are unchanged from the original forms."

Response: Your point that the "forms percent in the tank water are unchanged from the original forms" is absolutely valid. However, I said " leaching from the small surface area of PVC could lead to equivalent levels in a volume of several hundred liters". I did not intend to say that the molecular form of tin was equivalent, but that by the simple principles of mass conservation that the concentration of tin present in a small PVC pipe cannot lead to higher concentration in a larger volume of water.

4. "The amount present in some plastics is incredibly higher than 4 ppb. Like whole number percentages:

Polyvinyl chloride - Wikipedia

en.wikipedia.org

"Tin mercaptides are widely used globally in rigid PVC applications due to their high efficiency and proven performance. Typical usage levels are 0.3 (pipe) to 2.5 phr (foam) depending on the application. "

Response: I did incorrectly state that the amount of tin present in PVC was in the ppb range, but after careful reading see the document was referring to the amount of 'leachable tin'. You are correct, PVC contains a lot tin!

Curious then - do you have any PVC in your system? I mean - literally everyone (I dont) has these beautifully and artistically colored PVC pipes in all their tanks - with valves, etc to match. Are all of them at risk? Frankly - I dont see it. Many people use plastics. IMHO - its the same comment where a candle burning in a room - is going to cause a problem - unless its an extremely small tank - it would be interesting to see how anyone could justify a scented candle making a difference in a large tank ( as compared to a nano tank)

 

[Randy Holmes-Farley]

Curious then - do you have any PVC in your system? I mean - literally everyone (I dont) has these beautifully and artistically colored PVC pipes in all their tanks - with valves, etc to match. Are all of them at risk? Frankly - I dont see it. Many people use plastics. IMHO - its the same comment where a candle burning in a room - is going to cause a problem - unless its an extremely small tank - it would be interesting to see how anyone could justify a scented candle making a difference in a large tank ( as compared to a nano tank)

FWIW, I had lots of PVC and other plastics and no detectable tin, but it had also been in the tank system for many years and may have run it course of leaching years ago.

 

[Randy Holmes-Farley]

FWIW, folks should not focus in just big rigid PVC pipes. Folks have found that other tubing is an issue. Reefers have noticed it, as have scientists in the literature:

The unexpected sources of organotin contamination in aquatic toxicological laboratory studies - PubMed

Unaccounted sources of contamination can be problematic in toxicological studies and can range from the presence of impurities, breakdown products or isoforms of the parent compound to the unexpected compounds leaching from dosing apparatus. As these compounds are not being tested, they may not...

pubmed.ncbi.nlm.nih.gov

this paper we report the unexpected detection of butyltin compounds (mono, di and tributyltin) in flow-through aquaria waters of an aquatic toxicological set-up. High and variable leaching rates for dibutyltin of 2.0 and 6.6 microg/h were detected during the first week of each of two separate flow-through studies. Following this initial 'surge' of dibutyltin leachate, a decrease in leachate rate was seen with values of 0.9 and 1.2 microg/h by Day 14 (second week of study). The main source of the butyltin leachates was shown, to be the airline tubing used in the assembly of the air-supply into each flow-through tank. A 24h period of incubation of the airline tubing with clean water led to the leaching of concentrations of 63.8 ng/l TBT-Sn, 1638.8 ng/l DBT-Sn and 4054.6 ng/l MBT-Sn.

 

[Courtney Aldrich]

FWIW, folks should not focus in just big rigid PVC pipes. Folks have found that other tubing is an issue. Reefers have noticed it, as have scientists in the literature:

The unexpected sources of organotin contamination in aquatic toxicological laboratory studies - PubMed

Unaccounted sources of contamination can be problematic in toxicological studies and can range from the presence of impurities, breakdown products or isoforms of the parent compound to the unexpected compounds leaching from dosing apparatus. As these compounds are not being tested, they may not...

pubmed.ncbi.nlm.nih.gov

this paper we report the unexpected detection of butyltin compounds (mono, di and tributyltin) in flow-through aquaria waters of an aquatic toxicological set-up. High and variable leaching rates for dibutyltin of 2.0 and 6.6 microg/h were detected during the first week of each of two separate flow-through studies. Following this initial 'surge' of dibutyltin leachate, a decrease in leachate rate was seen with values of 0.9 and 1.2 microg/h by Day 14 (second week of study). The main source of the butyltin leachates was shown, to be the airline tubing used in the assembly of the air-supply into each flow-through tank. A 24h period of incubation of the airline tubing with clean water led to the leaching of concentrations of 63.8 ng/l TBT-Sn, 1638.8 ng/l DBT-Sn and 4054.6 ng/l MBT-Sn.

Sweet paper! The silicone airline tubing is leaching huge amounts of tin as you mention and leaching continued out to 2 weeks (the last time point shown). The total leaching from Figure 2 (by visual integration of panels A and B) is probably about 1000 ug of total tin leaching over the first 2 weeks alone. This could definitely account for the moderate tin levels observed by SifuMemphis. Their ICP report shows about 8 ug/L x 525 L (their tank size, I believe), which corresponds to about 4000 ug of total tin.

​

 

[Courtney Aldrich]

There's another thread on tin that includes experimental data on different types of tubing and come s to similar conclusions.

Tin Leaching from Common Plastic Tubing and a Very Inert Tubing that I Found

I'm sure many of you are tired of me posting about tin leaching from plastic, but for those having "tin problems" this might be helpful. Although I found tin leaching from many plastic products, I found that plastic tubing may be the worst culprit. I performed "soak tests" where I would soak...

www.reef2reef.com

 

[MnFish1]

the question.... in my mind if your tank looks ok who cares. to me the people selling these tests say no water changes until there is something abnormal .....

 

[Courtney Aldrich]

the question.... in my mind if your tank looks ok who cares. to me the people selling these tests say no water changes until there is something abnormal .....

I agree with you. I think ICP is cool, but it just makes people paranoid for no reason. If your tank looks good, I don't think it's necessary to stress out about trace impurities that cannot be easily addressed by most hobbyists.