Clever little detector/logger, Stuart! As mentioned earlier in the thread I've used OB method for many tests - had a few misfires now...

Thanks, Stuart, I get you on all that. We have a reasonably fast moving stream I'd say in the order of 20-30cm/sec - at least as far as...

I wonder what quantities you were injecting to turn both small (Barbon Beck) and medium (Dee) size rivers green! Last night I...

The 'detectors' will be people looking for it! ;) Yeah, I know I could put swabs in (have always done that with OBA), but then it's...

Thanks for confirmation (y) If I make up a solution, should it be released into the stream slowly?....so as to 'string out' the...

Thanks everyone for all your suggestions....and hilarious stories/anecdotes! - it sure is a substance to be reckoned with! Stuart...

Many thanks for the link, Ian (y)

I can vouch for this. Decades ago I used to work in a lab and I acquired fluorescein. As a party trick I used to drink it, twas...

In today's news: Confusion after canal turns green to find leaks I wonder how much fluorescein it takes to turn 8.5 miles of canal green?

Can anyone recommend a good supplier/source of liquid fluorescein dye (or perhaps pwder if that is the preferred format these days...

Do I have to, it's my favourite thread title in ages?

Here are a couple of snaps from the river tramp - Will and Tim and then Tim with the Benarat cliff and the Corner Cave up above in the...

Here are a couple of short video clips of the walk up the gorge on a beautiful day. Remember the video in the rescue story above - that...

I think he might mean Penguin Hall...which is the short pitch after the free-hanging 3rd pitch, at a convergence of several avens. And...

Great write-up, Tim, it all comes flooding back! ;) Looking forward to the next episode! p.s. I tend to agree that digging the lower...