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

[MnFish1]

Hello,

I also was have problem with Tin in my reef tank. Tin was about 70ugl, (I was have only high Tin without other heavy metals) all hard corals died. Even when I did 100% water change, all those corals that were still alive at that time died in the next weeks or months, as I suspect the poisoning was strong enough and the corals were already doomed.

I still don't know where the tin came from.
I did test for my tap water and RO/DI and there was not tin.
But I used plastic tubes for my dosing pump.

I would think its extremely RARE to have significant amounts of tin from dosing tubing. I have heard of it from certain types of glass, and also certain types of PVC plumbing (as compared to narrow tubing). Part of it depends on how big your tank is also (i.e. tubing in a 500 gallon tank is not likely to be a problem. tubing in a 2 gallon tank might).

I would also ask you - since practically everyone that has sent in an ICP test shows some elevation of tin - are you looking for a solution to a non-problem (i.e.- do you think its actually causing a problem)? Most people find it goes down with water changes quite nicely - and that if there is a problem with plumbing - that gradually, less tin leaches out

 

[Doreno]

I would think its extremely RARE to have significant amounts of tin from dosing tubing. I have heard of it from certain types of glass, and also certain types of PVC plumbing (as compared to narrow tubing). Part of it depends on how big your tank is also (i.e. tubing in a 500 gallon tank is not likely to be a problem. tubing in a 2 gallon tank might).

Im not sure that problem was in plastic dosing tubes, just noted this, that I was have this tubes

My tank was about 200 litres - this is about 200/3,78= 52.9 gallons.

I would also ask you - since practically everyone that has sent in an ICP test shows some elevation of tin - are you looking for a solution to a non-problem (i.e.- do you think its actually causing a problem)? Most people find it goes down with water changes quite nicely - and that if there is a problem with plumbing - that gradually, less tin leaches out

I was have good experience with reef keeping with my previous tank, in this tank I just did the same things, but all the time there were problems with corals, I could not understand what was the matter, because before that, as already mentioned in the previous tank, I did not have such problems. When I did ICP test, everything became more or less clear (for me), although I admit that there may have been other reasons and this is just a coincidence, who knows.

 

[MuscleBobBuffPants]

OP. Did you also send an ICP test of the water you started with to also get tested? Or the buckets alone with water and nothing in them? I feel like these “tests” need a lot more control than what we’ve read about here. How can we know the contamination isn’t from somewhere else?

 

[Dr. Jim]

I would think its extremely RARE to have significant amounts of tin from dosing tubing. I have heard of it from certain types of glass, and also certain types of PVC plumbing (as compared to narrow tubing). Part of it depends on how big your tank is also (i.e. tubing in a 500 gallon tank is not likely to be a problem. tubing in a 2 gallon tank might).

I would also ask you - since practically everyone that has sent in an ICP test shows some elevation of tin - are you looking for a solution to a non-problem (i.e.- do you think its actually causing a problem)? Most people find it goes down with water changes quite nicely - and that if there is a problem with plumbing - that gradually, less tin leaches out

I definitely agree with your first paragraph, but regarding tin leaching and reducing over time, I'm not so sure how quickly that happens. In my limited, 9-month "experiment", I saw no reduction in tin leaching. Also, considering that the tin is distributed throughout the product, and not just lining the surface touching the water, as the product "wears" over time, if that is even possible, there would be "new" plastic with more tin exposed to leach. This is just a theory, of course, but reasonable IMO.

OP. Did you also send an ICP test of the water you started with to also get tested? Or the buckets alone with water and nothing in them? I feel like these “tests” need a lot more control than what we’ve read about here. How can we know the contamination isn’t from somewhere else?

Yes, controls were included for the water source and the containers.

 

[Lowell Lemon]

Okay another possible source for Tin is the mold injected plastics coming from China. It is a fact that the will use the cheapest materials possible and not use the industry specific resins compounded in first world countries. All these "manufacturers" that depend on China to mold inject their pump parts and related have no idea what is being used. I mean if Chinese companies get away with using melamine to color infant milk and pet food do you honestly think they give a lot of thought to the plastics they use for mold injection? This is one reason I used other Eheim and Tunze for years to avoid the contaminated plastics from China. Sadly, both Eheim and Tunze probably have their mold injection done in China now days. The only way to control process is to bring back those industry's back to the United States or Europe at least.

 

[Randy Holmes-Farley]

Okay another possible source for Tin is the mold injected plastics coming from China. It is a fact that the will use the cheapest materials possible and not use the industry specific resins compounded in first world countries. All these "manufacturers" that depend on China to mold inject their pump parts and related have no idea what is being used. I mean if Chinese companies get away with using melamine to color infant milk and pet food do you honestly think they give a lot of thought to the plastics they use for mold injection? This is one reason I used other Eheim and Tunze for years to avoid the contaminated plastics from China. Sadly, both Eheim and Tunze probably have their mold injection done in China now days. The only way to control process is to bring back those industry's back to the United States or Europe at least.

I'm not sure I see this as a cheapness issue. Tin is a widely used and "touted" additive to plastics to improve performance.

 

[Randy Holmes-Farley]

Organotin stabilizers for high performance plastic sold by a German company (Baerlocher):

https://www.baerlocher.com/fileadmin/media/0.5_Service/0.5.1_brochures/0.5.1.3_product_brochures/2016/pb_organotin_stabilizers_12p_2016.pdf

 

[Lowell Lemon]

Organotin stabilizers for high performance plastic sold by a German company (Baerlocher):

https://www.baerlocher.com/fileadmin/media/0.5_Service/0.5.1_brochures/0.5.1.3_product_brochures/2016/pb_organotin_stabilizers_12p_2016.pdf

It is a cost issue for plastic molders. It is also an issue of using proper compounding for proper application.

You must have not seen the two examples in the national news over the last ten years or so with melamine.

I also have experience with the issues of improper compounding with Chinese Cell Cast Acrylic sheet.

I defer to you since you are the chemist.

 

[Randy Holmes-Farley]

It is a cost issue for plastic molders. It is also an issue of using proper compounding for proper application.

You must have not seen the two examples in the national news over the last ten years or so with melamine.

I also have experience with the issues of improper compounding with Chinese Cell Cast Acrylic sheet.

I defer to you since you are the chemist.

It seems "proper" compounding adds tin. It's not put in to cheapen the plastic.

 

[Lowell Lemon]

It seems "proper" compounding adds tin. It's not put in to cheapen the plastic.

Perhaps if I re-word this. Select only the proper plastic compounds for aquatic use. Do we agree now? All sorts of plastics are not recommended for aquatic use.

 

[Randy Holmes-Farley]

Perhaps if I re-word this. Select only the proper plastic compounds for aquatic use. Do we agree now? All sorts of plastics are not recommended for aquatic use.

Yes, but this implies knowledge that hobbyists and hobby companies do not have. Not only what is in the plastic, but also what to avoid. Both are lacking. Tubing manufacturers know only what is there, not what to avoid. Hobbyists and hobby companies may not know either one.

If you go to buy tubing from a high end supplier (say, Cole Parmer), they never state exactly what additives are in it, and Cole Parmer likely doesn't know. At best, they provide polymer composition and chemical compatibility.

It is true that there may (or may not) be an adequate market for a hobby company to source specific types of tubing with specific composition properties, which will likely cost more so they would have to sell it at a premium cost.

Or they can buy tubing and look for leached materials. But what would they look for? Sure, they can look for tin released. Is that the only chemical of concern. Might a replacement be worse than the tin?