Anti-foul for Transducers

Maybe it's really well known, but I didn't know so I'm sharing it. There's special anti-foul for the transducers. I'd never really known what to do about these, so I'd normally have left them without anything causing them to get all furry during the season. 

There's a thread on YBW Forums that suggests:
"I've never found a problem applying a thin coat of regular solvent-based antifouling on depth transducers"

It appears to be pretty scarce stuff in the UK, but available on Amazon.com in the USA. I found it on an Ebay auction, but there seems to be a huge mark up ($7 in the US, £22 in the UK).

I'll order some and report after results.