Is main drain necessary?

[JimK]

You will probably see a lot of opinions on this but I think you know my position if you read the thread.

Without a main drain you will see better performance out of the skimmers. But the study I posted should be enough to convince you:

http://www.poolforum.com/pf2/showthr...169#post126169

Yes, I did read that (thank you for posting that ). Your posts are what have me pursuing how my pool behaves without the MD, or at least with flow from the MD greatly reduced.

Do you know if the pressure drop I'm seeing at the filter when restricting the MD flow means there's also less flow coming out of the returns?

I'm always learning something new here.