Posted for "John Slade" <sladerj@bellsouth.net>:

Hi Paul,
The ideal is probably to return to the tank you're drawing from. This can be
achieved with an Andair duplex valve. To avoid the extra piping and expense,
I choose to use a solenoid valve which flips the return depending on which
tank I'm drawing from. Details at http://kgarden.com/cozy/chap21b.htm

I'd recommend putting return pipework in the strakes now, before you close
them. Rather than simply flox the pipes through the walls I used aluminum
flanges from Wicks which allow you to screw the fittings in. This way you
could plug the returns if you decide to go with the sump return. Having said
that, I put the pipes in after the tanks were sealed, and it was fairly easy
to do. Getting a proper seal on the right tank was a whole other story.
Regards,
John Slade