PCB's etching VERY slowly, muriatic acid and hydrogen peroxide
I recently started using the muriatic acid and hydrogen peroxide solution to etch PCBs. All of the boards I do at home are simple, single sided, and range in size from 1-4 sq. inches. The first board etched in a few minutes, the second 15 or better and now it is taking hours (after 5 or 6 small boards). I have the fish tank pump set up to oxygenate the mixture. The mixture is a nice green color, which from what I have read is correct. Any ideas on why it is so slow now or suggestions as to what I need to do differently?