where to reduce bottom drain

[Margo]

Hi all,

I'm gathering all the supplies I need to plumb my new pond. I seem to have one question outstanding. Where do I reduce my four inch bottom drain to three inches? I'd like to do it before the check valve and the knife valve so I can buy the smaller and less pricey units. Any downside to doing this? Or should I just bit the bullet and buy the four inch check and knife valves and reduce it right before the skimmer?

Thanks!
Margo

 

[Meyer Jordan]

I would not reduce it at all, including at the skimmer.