Is PCTG reef safe?

[cwills75]

I normally use PETG for 3D printing, but I've seen some ads for PCTG recently and wondering if anyone has any info if this blend is reef safe or not.

 

[Fish Fan]

@Reefer Matt would know for sure what's best

 

[Reefer Matt]

I haven’t used this filament yet, as it is newer. AI seems to think it’s good for reefing, but I’d defer to the chemical expert, @Randy Holmes-Farley for this.

 

[revoman]

Holding my breath for an answer to this one. :D

 

[servus]

I hope you're not still holding your breath :D. I hope it's reef safe, also. Will probably go with AI recommendation.

 

[Randy Holmes-Farley Verified Community Expert]

It has ester linkages that could slowly hydrolyze (break down) in water, and I would especially not use it for high pH things, such as kalkwasser contact, but the degradation may be too slow in tank water to be an issue.

 

[Defiant One]

It has ester linkages that could slowly hydrolyze (break down) in water, and I would especially not use it for high pH things, such as kalkwasser contact, but the degradation may be too slow in tank water to be an issue.

How is that different than PETG that many understand to believe reef safe as well? PETG also has ester linkages that can degrade in high pH water (levels higher than what is in reef tanks). It seems to me that PCTG can be a direct replacement for PETG with better properties and printability than PETG. Even PVC degrades over time especially from UV exposure but the PVC and CPVC used in my house has become very brittle after years of normal use, without UV exposure. I have to cut it with a saw to replace it because it just shatters with PVC cutters.

 

[Randy Holmes-Farley Verified Community Expert]

Pctg should be somewhat more stable to hydrolysis than is petg. Both may be fine if not in high pH uses.

Not sure what the comment on pvc relates to. PVC is oxidizing, not hydrolyzing.

 

[Reefer Matt]

I now use this material in my 3d printed designs. It is more durable in saltwater than petg and just as safe from my research and early usage. This prints with less stringing and has more memory in flexability, it doesn’t warp as easily when bent.