Homebrew PCBs

Hi again,

i have tested the hydrometer, and it shows that my current
etchant is at 1.19 density.

is there any way to test the hydrometer on it's accuracy?
i think i remember reading about using NaCl Solution
for this. How much salt do i need for making 1.2 or so and is this
possible at all? i mean can the water take that much salt?

Which range of density is ok for CuCl? how accurate must that be
for good operation?



I also made the 1 molar NaOH solution as described in
http://www.pacificsun.ca/~robert/pcb/cucl.htm.

But i have no Bromophenol Blue, can i use Methylorange instead?
can i follow the instructions for bromophenol blue or do i need
to normalize it or something?

I also have another question, i used tap water instead of distilled water
for mixing the etchant. do you think this was a bad idea?

The current batch of etchant i used for ages now, only adding H2O2 and HCl
whenever needed. i never added water.
The etching gradually slowed down, of course i can dispose of this lot
and make a new one (i will do that when the new etchant container is 
finally ready
maybe).

But i thought i might as well try to figure out what is wrong, and finding
the hydrometer made me do it finally.

thanks..

Stefan