Just noticed this strange effect in my plastic water butt. It is filled by the drainpipe. It looks like something is eating the algae from the inside of the butt, but I can't figure out what. Any ideas???
The first image has been digitally enhanced to show the effect more clearly. The second is 'natural'. the miscellaneous shapes are reflections from the surface of, for example, the waterspout.
I have seen this happen too, but I don't know what is at work.
I have seen that happen also but have no idea what causes it.
Definitely a freshwater oorganism at work there. :)
