Two stage watermaker pump

[Hoghead]

I am trying to get around the AC power requirements for a watermater pump and wonder about a 2 stage pump, whereby a small pump feeds a larger pump with 2 chambers.

I already have a Watermaker system and just need more flow than provided by my current dinky 12V pump

Any one know where to buy one of these 2 stage pumps?

[paulajayne]

Have look at pressure washer pumps - or even buy a pressure washer and pull it apart for the pump. Be careful of the cheap ones as the pumps are plastic.

[Lepke]

You can find used pressure pumps on ebay. You might run a belt drive off your main if you run enough in an average day to produce the water you need. With the volume a belt drive pump can provide you could run two membranes and make water twice as fast.
What pressure are you looking for? There are several aquarium R/O system pumps for low pressure systems on ebay. Also portable sprayer pumps run on 12 volt.

[Hoghead]

I am aware of pressure washer pumps, and the good ones with SS or NAB heads are about 1200.00 and more. A good CAT pump with a brass head is half that price.
A cheap pump is cheap and I am not sure how long it would last in 8-900 psi seawater. Same for a good pump with a brass head even if flushed after use