Setting up sump...

[MitchM]

Originally Posted by Wayne

Pipes are 1" and there are holes in the caps which do sit below the water line. How do you start the siphon or is it just a pressure differential that automatically starts it.

How do you determine over flow size? The boxes are 4.5" x 4.5" x 18.5" and the current tubes (which I will rebuild) are 18" tall. Thanks

Yes, that's what I meant about overflow size.
When you re-plumb your overflow drains, make sure to design it so that you can get your hand down to the bottom of the overflow for when (not if) you need to retrieve something.

It looks like the old style was a Durso type return and I also recommend changing that to a Herbie style. I had a Durso for a while on one of my tanks and found that the hole that should be at the top of the return pipes kept plugging up with salt creep.
When that plugs you get a constant toilet flushing sound in the background, which is just lovely to listen to when you're on the phone!

Mitch