Potable=OK?

[arkman]

I'm setting up a new plumbing system and have a couple of questions...
1) if NSF certified for potable is it ok for SW fish/inverts?
2) has anyone just simply used a PVC tube that's a inch or so lower than the water level as an overflow? I'd drill into the bottom (or back) of my Acrylic tank to go to the sump below.
-- there more than a few more questions
I'll set up different posts --- Thanks!

 

[arkman]

yep - I was thinking more like a 3" drain --- is there a calculation for gravity fed GPH???
Also, is it better to have the gravity retun go low into the display for added "gravity", or would the back pressure negate the extra "freefall"?

 

[arkman]

sorry - never got an answer on the potable=OK question. If plumbing is certified for drinking water is it ok for a SW tank? What about the pool/spa hose (its cool that its already corrogated and wont kink)