Whale Gusher pumps are great. I find them reliable, maintainable and effective. They come in two sizes. You want the bigger one.
I use one in the head, and one in the galley for fresh water.
Foot pumps have a secondary effect of greatly reducing your consumption of fresh water. If you have pressurized water, you can't help but to waste 3/4 of it. In the Bahamas where fresh water is hard to find and expensive, we used only 0.8 gallons per day per person. All the books say 1 gallon per person per day, but we didn't need that much. Of course dish washing and flushing were done with salt water.
We also have a second gusher pump connected to the galley sink drain. That allows us to use a deep sink, with the bottom only 1 inch above the water line. The pump acts as a check valve allowing us to leave the sea cock open when under sail and to drain the sink normally no matter what the angle of heel. To connect it, I had to make an adapter from the 2.5 inch drain pipe to the 0.5 inch gusher pump fittings. We have to explain to guests why there are two foot pedals side by side in the galley.
