Quote Originally Posted by Kerik View Post
Vaughn you are correct. Heating the developer releases water vapor resulting in an increased concentration.
FWIW, I use a large - 2 QT. Pyrex measuring cup with plastic lid to heat my PO. The lid minimizes evaporation and the vapor condenses on the inside of the lid.

As Kerik said filter the sludge and check the pH. Top off with fresh PO as the volume declines or add a little water to dissolve crystals at the bottom.

You are good to go.