I use commercial wetting agents at half strength and dump them after use. I like the idea about adding a bit of isopropyl alcohol to the working solution as a preservative, thereby not having to discard it, providing it remains clean. That means a bit less chemistry going down the drain. I always use HCA with film. It seems to help clear the antihalation backing form the more stubborn films. I have read somewhere, that wetting agents for film also contain anti fungal agents. if true that may be another reason for using them.