As I am inept at fishing out the fungus that grows on my Part A mix, always ending up with 'threads' across my images when I coat them, I have investigated remedies.

After 3 weeks, my latest batch of Part A has the usual white floaters on it, but at the time of mixing I decanted off 20ml and added 1ml of Listerene mouthwash and it is still crystal clear!

As a test I used the listerene batch for an image today and it works fine still. The added advantage is that if I am doing a sequence of images, the pipette I use for part A stinks of mouthwash and therefore I can identify which pipette is which and avoid cross-contamination of parts A and B.

Unfortunately I never did like the taste of Listerene and a 250ml bottle will last me rather a long time if it is only for preserving my Part A!