Do you know anyone who has used the fish street coil and is confident it's actually fully titanium? I'm nervous it of the quality and if it will leech unwanted metals.
I don't know of anyone using it, but I would be willing to give it a shot if it were me. I use a immersion titanium chiller, and this is basically the same thing. obviously the junctions are brass, so care would have to be taken to keep them out of contact with tank water. I also think that generally fish street does it's best to provide decent products- I would think they would have removed it if they had gotten complaints.