Dear Team Carpology, could you please make a test one day with how a heavy Bobbin compares to the Solar Titanium Indicator on a range for example of 150 Meter? Is it true, that the water drift takes the sensitivity out of the normal Bobbin and it drops down very slowly on a drop back?
Way too light, you need a bit of weight in a bobbin. You also need to design the bobbin to take an isotope in the centre, rather than a slot on the outside.