PM is easy to trreat - I float a tupperware of RO/DI water in my fuge for about 20 minutes to get it to temperature - then I dip the clam in there for about 15 mins - check out Barry's site (www.clamsdirect.com) for the treatment plans.
when i have done freshwater dipps i alwasy matched the temp and ph .. i was told it is a must but i guess not lol. it is actually quite intresting to watch. i never had any fatalities either
It is a good idea to match the temp & PH. keeping in mind that most of our local tap water here is about 7.2, so it is a wide swing to 8.0-8.4.
You never know if your going to run into a coral that just can't take that extra stress on top of whatever you are treating for...even if it's only a FW dip without 'medication' added.
The easiest way to get the PH to a level that will cause no added stress is to buy a package of "Proper PH 8.0" and add the appropriate amount for the amount of water you're using. It's good for FW and SW.
Why chance it?