Possible TIN Contamination?

hobbyreefer · May 16, 2020

A few weeks ago I received my results from an ICP test and I was alarmed to see elevated TIN levels. All of my equipment is new and I do not have any rusty screws or anything that I know of.

Today, I was looking in my tank and I noticed something shimmering. I pulled out a small piece of foil (picture below). This was wedged in a hole in one of my rocks. I'm thinking this might be the back of a frozen cube wrapper? Could this have caused the elevated TIN?

Larry L · May 16, 2020

What is your current reading for tin? Have you had a previous ICP test with lower levels of tin?

How new is the tank and plumbing? Tin is used as a stabilizer during the production of PVC. There's also some speculation that if a glass aquarium is built with any of the panes facing float-side in, then some tin might leach from the surface (since float glass is usually floated on tin).

Also, some forms of tin are a problem and some are not, but an ICP test measures them all and you can't tell them apart. Taking the liberty to quote a previous @Randy Holmes-Farley post in a different thread:

There is not, and really cannot be, definitive info on the exact values of tin that are an issue because none of us knows the form of tin present in our reef tanks. It's like asking how toxic is carbon. In the form of cyanide it is very toxic, in the form of glucose, not so much.

As noted above, about all you can do is note what other reefers observe and hope that your type of tin is similar to theirs.

In that vein, 30 ug/l seems to be about in the middle between those that have issues that they attribute to tin( rightly or wrongly) and those that have no apparent issues.

Randy Holmes-Farley · May 16, 2020

It is not particularly unusual to see elevated tin. It is unusual for it to be high enough to cause apparent issues.

hobbyreefer · May 16, 2020

Thank you both very much for the response. I attached my ICP. My Sn was 14 ug/l.

My tank is 7 months old. I've read other threads about low iron glass leaching Sn. I've also read about new PVC.

I only have SPS in the the tank. I have 25-30 frags all from Battlecorals. I have Monti's on the bare bottom and sticks on the rocks. All of my Monti's are doing well. I would say about 50% of my sticks are coloring and encrusting and the other half are mostly brown. I'm not sure if they are brown because of the Sn or because the tank is just new. I've only performed one ICP test. I plan to run another one in the next week or so to see how the Sn has changed.

I was really just wondering if it was possible that the foil wrapper I found in the tank could cause Sn? I don't think it's coming from my equipment. I guess it's possible it's the glass or PVC. I also have a bit of rust on my sump door hinge. Waterbox has already sent me a replacement. I've read that this can cause elevated Sn as well.