Simply Koi and More Koi

I have just discovered in the scope accessories there is a slide with a raised square section which I assume is for more lumpy items
But there is also a slide with a concave circle in the centre??? Any ideas?

Try putting some pond water in the small cup of the slide.

Great fun - especially if you get some water from a wildlife pond!

Cheers

Bob

I will try that, do you know what the slides are which looks like a small magnified bit but I couldnt tell any diff with the cam on the laptop...?