Pump to Drain Greywater Tank

[Contadino]

Hi,

Can someone recommend a pump for me to completely drain a small underground tank?  Being greywater, I don't want to leave any residue in there, or it'll get pretty smelly.  All the submersible pumps I've seen with float switches look like they only drain down to the top of the pump.

It only needs to lift about 2m high, and about 10m horizontally to another tank which will have a nice tap on the bottom so I can access the water.  Quantity-wise, it'll only be about 100 litres, a couple of times a week. Mains or 12v, I'm not fussed.

Thanks.

[Rooster]

The cheap submersible pumps with float switches will drain right down to the floor, they're often referred to as 'floorsuckers'. However they won't do this if you rely on the float switch as that operates to switch off before the water gets that low, so you have to keep the float switch up to pump this low.

I often use one a bit like this one ......


http://cpc.farnell.com/blackspur/bb-sp151/water-pump-dirty/dp/SI15524

As an example you can pump a bath out completely, barring about a cup of water, so long as you hold the float switch up.

However these pumps don't like/aren't designed to be being permanently installed so I'm not sure if that's what you're after. So long as you don't mind chucking it in to pump and then removing it till next time it should work fine.

One problem with these types can be priming them. They're fine if you start with an empty hose/pipe and chuck them in the tank however if you leave them in there and they drain back a bit they often won't pump again without removing them, draining the pipe and starting again!

There are loads of this type around B+Q, Lidls, Argos and the like all sell cheap ones.

[Contadino]

Nice one. Thanks. That was just the answer I was after.

[tris1331]

Machine Mart (and no I don' work for them) have a good selection.  I have one of these:

http://www.machinemart.co.uk/shop/product/details/hippo-2-1in-submersible-water-pump/path/submersible-pumps-clean-water

There's no float switch so no need to get your hands wet or rig something to hold the float switch up.  Its not as cheap as the previous chaps linked item but it will do the job no problem.

[billi]

google for  " Bilge Pump" used on boats  some have a switch inbuilt  , so it sucks your tank out completely to the bottom

like this one http://www.yachtmailchandlery.com/rulemate-automatic-500-gph-12v-electric-bilge-pump-p-246.html

billi

[tony.]

hire shops sometimes sell them- we call them puddle pumps the self priming type

tony