"BenignVanilla" wrote:

"John Rutz" wrote in message
...
snip
go with the largest pipe you can, my mag drives have 1 in outlets but to
get full capacity(GPH) out of them I use 2 in pipe, Im redesigning the
filters and moving em farther from the pond so am planing on going to
4-6 in pipe

So 4'' for my bottom drains, skimmer, filter, all runs?

Some of that depends on the parts you select. IE I've seen in pond
skimmers, that hook up to inch and half. Kinda a waste to run 4 inch
pipe only to neck it down that much, since most pumps don't take that
either.

4 inch is good for gravity flow lines, pressure lines, those connected
up to a pump, are usually smaller, based on the size the pump takes.

Typically it is feasable, and desirable to go up one pipe size from the
fitting, thus an 1.25" threaded pump output, would go to a
1.25NPTto1.5slip PVC fitting, and be plumbed with 1.5 inch pvc pipe.

That is how I have my current setup, an in pond pump goes out with that
fitting, 1.5 inch flex pvc to 1.5 inch sched 40 that feeds my upflow
filter (150 gal stock tank) which exits via a 3" pvc pipe, up near the
top of the tank.

Now of course, your pond and pumps might be sized for 4 or 6 inch PVC.
I have a piece of 12" sched 80 PVC that was donated by a buddy as
surplus from work, it is going to be a while before I need to use that
in MY pond. G