Thermometer broke in tank, Mercury balls

[Gowalkitoff]

Today I noticed my thermometer was broken, a circular area of glass at the bottom of it is missing and when I removed it from the tank, somw of the little gray balls fell to the gravel which BigAls advised me are mercury. 

Upon close inspection of my gravel (white, thankfully) I can see them, and some have been there long enough to be rusty.  So my Jack got rowdy at some point Im assuming and knocked the thermoneter against the tank. 

So aside from hoping I find the piece of glass, I have carefully cooped out all the gravel from the area and am going through it all with tweezers, sorting out gravel as the balls fall to the bottom of the plate.  Siphoning did not work. 

Aside from what I'm doing, how do I ensure my water is safe?  Thanks.

[Mike L]

It can't be mercury as it  is liquid at room temp. Those balls are weight to keep the thermometer bouyany. The fact they rusted would lend credence to that as well. In the case of fish tank thermometers they are likely filled with alcohol based fluid.

[Gowalkitoff]

Thank goodness!  I don't think the liquid part broke.  I don't understand how this even could have happened.  My husband suggested i not bother sifting through the gravel (I was removing the rust stained gravel too) to save frustration so I just tossed what I scooped out. 

[limmer]

I don't have any thermometers in my tanks.
I use something like this to test my water.
https://www.canadiantire.ca/en/pdp/starfrit-digital-thermometer-1425713p.html#srp.
I think I picked it up at Winners for around $10.
I would test it against a good one as I don't think ANY are totally accurate unless you spend a lot of money.
Just add or subtract degrees to get a reading.

[HayleYoyo]

mercury thermometers have been illegal for a VARY long time.

Those packaging say 'mercury type' thermometers, but that is just marketing.

[Gowalkitoff]

Ok thanks.  Should I be concerned about any water issues from the rust?  Should I use some carbon to remove any impurities?  I have an eheim 4+ pro