Serendipity strikes again! After thinking up the idea for a dancing water fountain, I was stumped on where to find pumps to circulate the water, but remembered that Harbor Freight somtimes has pumps for outdoor waterfall displays. I checked their flyer that I had just received, and they had not one but two different small pumps on sale this week, for $5 and $10! One of them even specifically listed tabletop fountains among its applications!
I dropped by Harbor Freight last night and bought both pumps. After trying them out in the sink, I’m pretty sure the larger one will work for my fountain, although the smaller one sure is cute. 
Smaller Pump
The smaller pump is Harbor Freight item number 45303, rated for 66 gallons per hour. It has a 1/2″ outlet and a 1/4″ adapter, which makes a stream barely larger than what I’d like for one of the jets in my fountain. It was on sale for $4.99, regularly $9.99.
When I first tested it, I had it stuck flat on the bottom of the sink, and its own water splashing down on top of itself disturbed the surface of the water enough that it was trying to suck in air, and the water stream “lurched” as it got water, didn’t get water, got water again, etc. Then the suction cups on one side popped loose (mental note: don’t expect the pump to stay in place under power of its suction cups alone) and it leaned to one side, making an arc of water that was much less disruptive and more photogenic.
Not large enough to power eight (or sixteen) jets, though.
Larger Pump
Perfection! Harbor Freight item number 41287 is rated for 190 gallons per hour, which turns out to be more than I think I’ll need, but it’s adjustable. It has a 1/2″ outlet that makes quite a stream! It was on sale for $10, regularly $17.99.
The inlet has a rotating “switch” (visible in the photo on the Harbor Freight web site) to limit the amount of water taken into the pump. The photo above shows the amount of output at the second-lowest setting, which is about as far as I wanted to go in the sink–but it can put out a lot more water if it turns out that I need it. This is definitely the right pump for this project, and it was CHEP! Hooray!
Several observations:
- I think I’ll want to build a completely submerged enclosure for the pump. That presents the complication of making good enough seals to get the power cord and the outlet tubing through the enclosure without leakage. It also complicates replacing the pump if/when it fails.
- While prototyping, I’ll need to be able to access the inlet “switch.” That means that I can’t seal the pump into its enclosure until I’m sure I know which setting will provide the right amount of water.
- From what I can see of the impeller design, the pump won’t suffer if its output is constricted or cut off entirely. That reduces the need for a bypass valve and simplifies my work.
- I looked for clear tubing in the store to go with the pump and couldn’t find any, so I’m kind of annoyed that they list it for cheap (25′ for $3) on the web page right next to the pump.