Filters for a large pond

Hi all,

First time posting here. I am in the process of working on a larger rubber
lined pond (about 210,000 gallons). I am trying my best to get it to
sustain itself but as I get into the pump and skimmer parts I am looking at
my options for filtration.

I guess up front I should let you in on the pond itself. At the deepest it
is about 12' deep. I have ledges that vary in depth from 2' to 4' around
the edge, which I plan using for plant life. I also have a low area which
is about 800 sqfeet total at about 9 to 18 inches deep for plant life (and
hopefully a natural filter system). Later I plan on creating a stream into
it that will run about 70' and drop a total of maybe 8' over that span.

I did build a fairly larger skimmer and basket from scratch ( 3' x 2' ' x 2'
deep) and have a 3" pipe off of that supplying a temporary setup to a 1.5 hp
pump (recycled from a pool). This pump is returning the water to the top of
the pond through a 1.5" pipe, and I have a reducer to create a nice jet.
Seems to work well as the top water is spinning into the skimmer.

Now I am looking to extend the buried piping about another 8' into a shack
that I am building on an exsisting concrete slab (say maybe 12' x 8'). In
this I will house my pumps and other related matter.

So here is my thinking. I ran the 3" pipe from the skimmer to allow me to
run two pumps. The 1.5hp that will return water to the pond. And another
pump (to be purchased) to run water up the hill to the top of the stream.
I also imagine I could valve the plumbing right so that I could have either
pump do both jobs (pump up hill and return water to the pond in case
something went wrong).

I am also thinking that either a bio filter or a sand filter is in order. I
have access to some cheep 55 gal barrels but am having a hard time finding
any link through Google for plans for a decent one.

Now I do know that according to some of the data that I have seen, there is
now way that I could filter the entire pond through a sand or bio filter. I
would like the pond to be self sufficant in that regards, but I do feel that
if I could put a couple of decent size filters in place, it would help from
time to time as needed.

Some questions that I have on the bio filters :

1. A good link to a website with plans. I am looking for an enclosed system
that will be pumped through and not the water fall type that I keep running
into.

2. I have read in a couple of places that for a bio-filter to be effective
it needs water running over it 24/7. I would like to avoid this due to $.
Any truth to this?

3. If I do run a bio filter (or a sand filter for that matter), should I
send the return water up to the stream, or return it to the pond?

4. Obviously I would plumb the bio filter so that it can be on or off.
Anyone see an issue with this? Or should I set up a cycle that flushes it
out for a set period each day? As I would like the pond to sustain itself.

Some questions I have on a sand filter :

1. Should I even think about it for temporay use? One reason I was
thinking of making one was for cleaning of the bottom as I have no bottom
drain (opening doors on that one).

2. I was thinking of using a submersable fountain as a type of bottom
drain. Get some of the sediment from the bottom mixed with the water and
then let it get to the filters.

3. Again any links to a website that has decent plans for a sand filter?


Also any comments on pump sizes. I am wondering if 1.5hp is too much for
the skimmer and I might be able to drop down to a smaller pump and use the
1.5hp to pump up the hill.

And last but not least. The concrete slab where the pumps will be sitting
will be about 1.5' higher then the water level. Am I to assume that
back-flow valves will solve my problems once I get the pumps primed, or
should I be looking at self priming pumps?


Any comments would be appreciated. I have thick skin so if I am doing
something wrong have at it.


Thanks,
Chris