Homebrew PCBs

You should try with a pump that has no-metal parts in the impeller. I 
am very impressed why in this forum almost nobody seems interested in 
building a spray etching system. That is the disadvantage of the "home-
brew" point-of-view. When you want to go like the pros, nobody seems 
interested. By the way, with a home-build spray ecthing system I was 
able to etch an 30x30 cm double-sided board in 4 minutes with ferric 
chloride at room temperature, with excelent resolution.