Are rubber pipe couplings reef safe?

[Doug/Shirley]

Are rubber couplings safe for the reef tank plumbing? I would like to use one in place of a PVC union due to space constraints on the discharge side of a pump. These go under one of several names Fernco, Pipeconx etc..

 

[cloudancer]

I don't know if they are "reef safe", but I've not had a problem with the one on my tank so far. I've had it on for about 2 years.

I have clams, fish and soft coral in the tank with the union.