I'm planning a upper level pond - approx. 6ft x 4ft, various depths
with deepest point probably being 1.5 feet. This upper pond will
basically serve as the head pool for the cascading stream. The stream
will have a series of small falls (this is a natural downward slope)
and will be approx. 20 ft in length and 3ft wide. This will end in
bigger falls to the larger pond which is about 12ft x 18ft and 2.5ft
deep.

I plan to use a Sequence pump and a 100 gallon stock tank to make a
"Skippy" biofilter.

I am having problems with the plumbing schematic and calculating
friction loss. The pump will have to push water up an incline slope
to the highest discharge point at the biofilter. I am guesstimating
the head at 15ft. Most piping will be a straight line run except for
elbows into the biofilter and two on the biofilter discharge to the
small pond.

What size Sequence pump would you recommend? 2" diameter pipe? Will
it be ok to place the biofilter parallel to the top pond? How do you
house your external pumps? Links, advice, etc. appreciated.

Thanks in advance.