What's the inlet size on the clarisea? I have a 350 reefer I think it 32mm on return pipe?
I went with 1" pvc but I had to wrap the pipe with teflon tape a few times. Now, the Clarisea website states 32mm but mine had a 1" marking on it, I could've glued it as is but wrapped it for a tighter fit in case I wanted to disassemble it later.
Edit: I hard plumbed off the Red sea drains so I'm not sure if the stock drain will fit the Clarisea.