Advice about tanks and med "leftovers"

[Zoaelite]

As a general rule, if you have used copper theres no looking back :\ Its a better idea just to start new otherwise even the smallest trace amounts of copper will cause haveck.
Levi

[Murminator]

I used a 20g for over a year that the silicone was stained green from to much copper with no problems

[KrazyKuch]

The copper will get into the silicone and it will leave a film on the glass.....so at the very least you should scrape all the silicone and re-apply it scrub the glass well with water a vinegar!