Homebrew PCBs

I have been using H2O2 from the pharmacy / Muriatic Acid combo, 2:1 - works well and is easy to get, but it doesn't work after the initial use.  It seems every etch, I need to make a new batch.  The etchant turns into a bright lime green color on the first etch and it does what I need to pretty quick and it seems like there is decent activity - bubbles which only happens on the first time use, after that maybe bubbles when I first put in the pcb/Cu but they go away very quickly.

After use, I will put the solution in a clear, sealed glass container and even if I use it the next day, after I start, 45min later my etch is still not done, so I dispose of it and make a new batch at which time I am done in 15mins.

What am I doing wrong or where is the mixture out of balance?  Again, I just did an etch this evening and had to make a new batch, which is now a bright lime green color.

Thanks in advance,
Bob