Homebrew PCBs

Hi to everyone. Do somebody has experience using/building a spray 
etching tank (the kind similar to Kepro, or even more proffesional 
units)?
I am looking for suitable pumps to recirculate FeCl from a tank to two 
spray bars for double-sided etching. I have been used the Bungard 
systems and they provide an outstanding quality and etching times 
(around 2 minutes for a 30x30 cm double-sided FR4 board). And they 
operation is relatively simple, so I am planning to build my own. Since 
I can not open the Bungard to see what kind of pump it uses, I would 
like to know if someone know more about the pressure or liters/min of 
similar pumps.
I am also intrigued about another system that uses a rotary sprinkler 
pipe and also performance very well at room temperature. Any 
information will be truly appreciated.