On Friday, April 24, 2015 at 5:25:58 PM UTC-4, J Burns wrote:
On 4/24/15 12:15 PM, trader_4 wrote:
On Friday, April 24, 2015 at 12:06:09 PM UTC-4, Oren wrote:
On Fri, 24 Apr 2015 07:45:50 -0700, "Bob F"
wrote:

http://www.amazon.com/Wayne-Systems-VIP50-Submersible-Utility/dp/B000CQ6CU4/ref=sr_1_10?ie=UTF8&qid=1429875701&sr=8-10&keywords=trash+pump

Needs only 1/8". 2500gph through a garden hose.

"Minimum water level to operate pump is 2 5/8-inch"

+1

That puts us back to the original subject question.

I'm not sure exactly what those specs need. It says both:

Needs only 1/8"
Min water level to operate is 2 5/8"

It probably means that it needs 2 5/8" to get it going, but once
going it can drain it down to within 1/8" of the bottom.
I have a pool cover pump that works like that. I use it
to drain my spa. It needs a couple inches for it to prime
and go to work, but will keep going down to maybe 1/4".
I have to be careful, because if it's not positioned properly,
or gets disturbed when it's down to say 1", then it won't
re-prime and continue, so you wind up with 1" left instead of 1/4".

If you weren't there to shut it off, and it got down to 1/4" and started
sucking air, could it be damaged?

I doubt it. But I only use it to pump out a spa, takes about an hour
or so and I keep an eye on it.