Copper

[Ocean]

the normal reson for the silicon changing color is copper but i ahve never dosed coper and all my inverterbates look fine and happy its only by the overflow nowhere else

thanks

 

[Kanga]

Manya other reasons why it would turn colour so I would not stress

 

[Ocean]

cool i just did not want wake up to a fish only tank over night lol

 

[AndreT]

Like Kanga said. If your corals are happy don't sweat it.

 

[Ocean]

so what could be cousing it?

 

[Warr7207]

so what could be cousing it?

Algae

 

[Tom]

I think the silicone did not take there and it is just algae growing, try and rub it off. Use a credit card Kryo`s idea.

 

[Ocean]

I will try then tell the news of my findings