Luckily it seems to be located between the black plastic strip and the glass, so all I have to do is keep the water level slightly lower.
I'm considering re-starting the pico however, and removing the sandbed, it just takes up too much space. And I don't intend on having any fish in there, so nitrates shouldn't become a problem anyhow.
Well I've gone and stripped my little pico down for now. Going home to England for a couple of weeks and don't feel confident in leaving the pico in my mother in-laws hands.
Don't know if I'll ever redo this particular pico, but I feel I've gained some knowledge of how pico's work and enjoyed producing it.
