Expiration date?

lol sorry, just what JRR said reminded me of my friend. So...what happens exactly to the chemicals once the expiration date is reached? I only run two tanks, one is a 46g bowfront and the other is a 20g quarantine tank...and I use Prime so that stuff goes down realy slow (I do about 50% water change every week). Do the chemicals just stop working or waht
 
Every single chemical is going to be different. As mentioned earlier many probably dont expire. It depends more exactly what your referring too.
Some will oxidize, others will decay, some will denature and some will have lost potency through ingredients evaporating out of solution. As he said, depends on the chemical itself.
 
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