Re: Aquatic Plants Digest V2 #45

On Sat, 29 Jun 1996 03:39:02 -0400, Aquatic-Plants-Owner at actwin_com wrote:

>The infrequent mention of the use of PVC, here, tends to make me 
>nervous. There is a special formulation of PVC called "CPVC" that is 
>always required for "potable water" applications. IMO, that's the only 
>kind we should consider for any extended contact with our tank water.
>Unfortunately, the ANSI standards for CPVC have been deliberately 
>designed to make it a total non-fit with any ordinary PVC, so a plumber 
>can't cheat and substitute a PVC fitting that has noxious aromatics in 
>its formulation. You can't mix and match or adapt from one to the other 
>(without a machine shop). 
>It's also sometimes hard to find. I've been running two copies (in 
>CPVC) of the ancient tube-type UGFs, under 30 mesh sandblasting sand, 
>for a year or so with no ill effects. The 1/2" size is smaller than 
>PVC, and just perfect for UGF (USF?) applications. I like it.

While CPVC might be safer for humans regular PVC is fine for fish.  I
have used it in central systems for years as have serveral friends.  
There are also published references as to the safety of PVC.  In the
book, The Dynamic Aquarium, ISBN 0-12-043790-2 Adey and Loveland mention,

"We use PVC piping or Tygon and similar tubing.  Where lighting is
intense, fouling is less in dark PVC; we have had no indication that
dark PVC is slightly toxic, as has been suggested."

Adey and Loveland's reasearch was done at the Smithsonian Institution's
Marine Systems Laboratory and involved, salt, fresh and brackish systems.

Ed Tomlinson (tomlins at cam_org)
Montreal, Canada

Home of pppdial: http://www.cam.org/~tomlins/pppdial.html