Homebrew PCBs

I've used up my Ammonium Perchlorate so I got HCl and H2O2.  I
understand that I need to use a bubbler to regenerate the etchant and
have seen references to letting it run a long time.  How long should I
expect - hours? days?  

Currently, my bubbler is a piece of vinyl tubing that I drilled #70
holes in,  This produces somewhat large bubbles.  I'll try it but do
those of you that use CuCl recommend something different, like an
aquarium airstone?

I'll be using about 3 Liters and doing a number of double sided boards
in the 10x15 CM size range, 1 oz copper.  I have an aquarium heater
that will bring the temp up to about 100F (about 38C) if that matters.

Thanks
Phil