Roy took care of questions one and two. For three, there are several
different bottom drains, and some homemade equivalents. Most have an
antivortex cover over the bottom drain to make the drain sweep an area of
the bottom, rather than creating a small vortex that pulls the water from
the top. Some of the bottom drains are through the liner, and a lot of
people are afraid of putting a hole in the bottom of the pond for fear that
it might leak. These tend to be the best, since they are 3 or 4 inch pipe
drains. There are a couple of retro fit bottom drains that can be used that
sit on the bottom, and use pipe within the pond that can come up and over
the side of the pond, therefore no holes. My drain is a through the wall,
about 8 inches down from the water line, and then down to the deepest part
of the pond. If mine were to create a catastrophic failure, I would lose
maybe a foot of water from a 3.5 foot deep pond.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"nortyler" wrote in message
oups.com...
Thanks for the input,

I have a few quick questions about external vs. submersable pumps and
filters.

1. Does an external pump need some sort of pump house (cover) to keep
it out of the weather?

2. Do the leaf strainers that come with external pumps collect leaves
or do they just keep the leaves out of the pump? Do the strainers sit
on the bottom of the pond and if they do will they pull the muck
through an external filter(ie veggie, waterfall)or do you need some
other device?

3. Are there different types of bottom drains? When looking throuh the
internet adds there seemed to be what was like a conventional drain and
also a device that sat on the bottom and connected to a skimmer.

I probably will start with just a pump and would like to add a filter
of some sort. I don't know if I have room for a veggie filter. How good
are waterfall filters?



Thanks,

Nort