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Broken thermometer - mercury in tank

6K views 9 replies 5 participants last post by  sk8rvendz 
#1 ·
A friend of mine has 3 fish tanks at home. One houses a couple of dwarf pea puffers, another has a male betta, and the third has a red-eyed puffer.

She phoned me in a panic yesterday because the thermometer in her dwarf pea puffer tank had broken, and there was mercury all over the place in the tank and she couldn't get it out... she wasn't sure whether or not it was safe to keep the fish in the tank with all of that mercury, but would also be unable to move the dwarf pea puffers in with either of the other fish.

I told her I didn't think it was a good idea to keep them in the tank with the mercury, and suggested that as a temporary solution, she could set up a bowl for the betta with some of his tank water and some of his gravel, and move the dwarf pea puffers into the betta tank for the time being. I figured out of all of her fish, the betta would probably be the most hardy. And, I hate to consider this a factor, but the betta would also be the cheapest and easiest to replace, since the puffers were all special orders... seems callous to think of the economic side of things when they're all living creatures, but it's still true. I stressed to her today that the betta needs to get back into a tank ASAP, or at the very least, she should have a heater in his bowl... hopefully he's not too upset about being rehomed for a short time.

Today she was talking about how she was having difficulty getting all of the mercury out of the tank... she worked at it for 4 hours and still couldn't get it all out.

Is it safe to put the fish back in? Should I tell her to just dump EVERYTHING and make sure it's all gone, and then start over? Is it safe for HER to be around it, even? Mercury scares the crap out of me... and I think it's better to be over cautious, but how much is too much caution? I don't want to be overly paranoid about it and make her go to waaaaaay too drastic of measures, but I don't want to tell her it's all fine and dandy if it isn't.
 
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#2 ·
Wow! I've never dealt with mercury in tank before but I broke one before and was told to wash my hands immediately after it dripped to my hands.

The thermometers sold nowadays though are alcohol-based, not mercury-based. And where I live, mercury-based thermometers are banned due to the dangers they pose.

Was the liquid inside silvery in color? I believe that she would have to dispose everything in contact with mercury except the tank itself. It's poisonous. I dunno though if the decors like gravel can absorb that but I'd just dispose them anyway. It's hard enough that it may be absorbed and removing it seems extremely difficult.

Your plan to switch fish around is fine. I can understand how that works out.:wink:
 
#4 ·
Wow! I've never dealt with mercury in tank before but I broke one before and was told to wash my hands immediately after it dripped to my hands.

The thermometers sold nowadays though are alcohol-based, not mercury-based. And where I live, mercury-based thermometers are banned due to the dangers they pose.

Was the liquid inside silvery in color? I believe that she would have to dispose everything in contact with mercury except the tank itself. It's poisonous. I dunno though if the decors like gravel can absorb that but I'd just dispose them anyway. It's hard enough that it may be absorbed and removing it seems extremely difficult.

Your plan to switch fish around is fine. I can understand how that works out.:wink:
I never saw it, but her description of it is unmistakable - silver, heavy/denser than water (it has all sunk into the gravel), beady... it's mercury.

I'm not sure if mercury thermometers are banned here... i think she got the tank used though, so who knows how old that thermometer was... maybe from a time when mercury was the norm?
 
#5 ·
I agree. I had not seen one though since the 90's when I accidentally smashed one.

I never saw it, but her description of it is unmistakable - silver, heavy/denser than water (it has all sunk into the gravel), beady... it's mercury.

I'm not sure if mercury thermometers are banned here... i think she got the tank used though, so who knows how old that thermometer was... maybe from a time when mercury was the norm?
Yeah, that's mercury to me. I'm so confused myself how she got one. It's possible her thermometers were extremely old already though.

Just dispose the substrate in touch with it. Has it touched decors as well?
 
#7 ·
That's good to hear.:smile:
 
#8 ·
When I was a kid (a very loooong time ago) my sister and I used to break thermometers so we could watch all the little swirly balls of mercury. What were we thinking???? :shock:

So, what is inside the thermometers I now have, if it's not mercury??
 
#10 ·
Best choice was to dump it all. Mercury is very dense and will leach into anything it touches. Then, over time, it will leach back out into the water. There are chemical methods to extract and purify murcury, but all of them im familier with would be expensive, dangerous, and completely alien to an aquarium environment.

Although, it should share properties with zinc and cadmium. That being said, you could rinse the aquarium with a higher than suggested solution of tap water conditioner a few times. Then rinse again with fresh aquarium water before you rebuild with fresh substrate and cycle it.

Hope it worked(s) out!
 
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