Thermometer broke open; how to know if the tank is safe?

[Rube_Goldfish]

I have a tank in which I just discovered a broken glass mercury thermometer.

At the moment, there are no fish in the tank, but the bladder snails and isopods* don't seem affected at all. I have Sera multi test strips and the API master test kit but obviously have no way to test for mercury. Can I use the snails as the canaries in the coal mine? If they're fine, fish would be fine, too?

*I think, anyway; they're small white dots zipping around.

[Rube_Goldfish]

I should add more detail: this tank held, up until sometime yesterday, a single pea puffer; we found her dead yesterday evening. The parameters tested out a little high on GH, KH, and pH, but otherwise fine, and the fish had no obvious injuries or illness. I chalked it up to the too-high GH/KH/pH and did a 90% water change in the anticipation of moving another pea puffer into this tank.

Now I'm wondering if the previous puffer ate one of the small metal (?) beads that fell out of the bottom of the thermometer. I guess I'll have to fish them all out before putting another puffer in there.

[AllFishNoBrakes]

I had a thermometer like that break in one of my tanks, but it broke at the top and I found it submerged on the bottom of the tank. 
 

Your guess is as good as anyone else’s I would say!

[FLFishChik]

Rarely do thermometers contain mercury nowadays. If the liquid inside your thermometer was red/reddish color then is probably either petroleum or Alcohol  (most likely alcohol) and is in such a small amount that it will not harm your fish. 

I did find this… 

[Rube_Goldfish]

On 4/12/2024 at 5:48 PM, FLFishChik said:

Rarely do thermometers contain mercury nowadays. If the liquid inside your thermometer was red/reddish color then is probably either petroleum or Alcohol  (most likely alcohol) and is in such a small amount that it will not harm your fish. 

I did find this… 

Thank you, yes! It looked just like that one! I'll clear out all of the balls but will otherwise confidently move the new puffer into this tank.

[johnnyxxl]

I don't think we have mercury in thermometers for years it was silver in color, I had one it was from the 50's I think.

[Lonkley]

The bigger issue is shards of glass. Hopefully it disappears into the substrate and it doesn't bite you in years to come. You could try vacuuming to see if any small loose stuff comes up.

[Rube_Goldfish]

On 4/13/2024 at 8:40 AM, johnnyxxl said:

I don't think we have mercury in thermometers for years it was silver in color, I had one it was from the 50's I think.

I guess I'm just living in the past!

On 4/13/2024 at 10:20 AM, Lonkley said:

The bigger issue is shards of glass. Hopefully it disappears into the substrate and it doesn't bite you in years to come. You could try vacuuming to see if any small loose stuff comes up.

The glass seemed like a pretty clean break. I vacuumed and turkey baster-ed the pellets up as best I could, then added some spare sand into that spot to bury any I missed. After that I realized I could have used a magnet, but figured there likely weren't any left, and if there were, they were already under the sand.