These are pricey but they work really well. They can run dry without harming the pump, they don't have to be installed below the waterline. No impellers to replace. They are self priming and have good pressure. Just be sure to order the one with the largest diameter tubing to get the most volume if you decide to get one.

http://www.smartcart.com/greylor7/cg...tem_num=RF-100