I'm planning a pond. The books say 'put in a bottom drain to make cleaning
easier.' The (few) people I've actually spoken to say 'don't put a hole in
your liner - don't need a bottom drain.

I plan for about 1500 gallons, 24-30" depth. Probably no Koi, because I've
heard they generate a lot of waste (and get huge).

What's the feeling on bottom drains?

Don't repeat my mistake. Install a bottom drain. I built my pond
(7000G) to have tons of crap collect at the bottom. It was basically
impossible to clean it out in any reasonable manner without adversely
affecting fish.

All the crap sitting on the bottom also gets constantly stirred up by
the fish making it harder to see them and increasing likelihood they
get disease and sickness.

So, yes, install a drain, why?

- It's not really that hard to do. About the labor equal to 1-2
thorough
pond cleanings without a drain.
- It will mean much clearer water.
- Do you really want your beautiful fish swimming around in their
poop
waiting for you to stir it up (in which case they choke on their
feces)
and then clean it out?
- It makes maintenance much much easier.

You could probably get away with a 3-inch on that pond which isn't too
expensive.

I didn't install one, and just finished adding two 4-inch drains and
moving fish back in yesterday. The water just keeps getting clearer
every time I look at it and there is basically nothing on the floor of
the liner. All the leaves, solids, and other crud gets sucked right
out of the pond into the pump basins for flushing.