Thanks Brett, for reminding us Lagoon
owners of yet another job.
Prevention better than cure, I suppose.
Your suggestion should work
well, but I think I'll just insert a plastic tube to the bottom of the tank, suck out a liter or two of fuel and look at it in a glass jar.
We have glass bowls under our primary CAV filters and haven't got a drop of water in them, so don't anticipate much gunk in tanks.