Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
Hi Adam,
6 inches or less is fine.  That leqves about 1 inch between the primary and
secondary.
Cheers,
        Terry
At 07:11 PM 2/7/2002 -0500, you wrote: 
>
> my primary is 8" at the beginning and i was wondering how big of a pvc pipe i
> should use for my secondary. I am thinking 4-5" 
> Thanks!!
> Adam