I should really have explained my container, it's kind of like one of those cheapo 'Washing up bowls' you put in the sink? I don't know if you have similar bowls in Canada..?
Kind of a squat shaped bucket, so the liquid will be viewed from the top only, as it's not transparent.
So I don't think that method will work (Or maybe I have it wrong?)

Hmm maybe if i just make a sheet of glass? Hmmm.... will give it a go...
Regards Scraggy