My tent doesn't have a SIG, so we get flies too - usually the really tiny ones! 'We get fewer when we have the groundsheet down in the living area - so do they come up from the ground? Best thing is to ignore them I think. We are, after all, invading their territory! My tent is also light blue at the top with a mesh vent near the roof, so being insects they seek the light and congregate up there - so they're easy to ignore!! We do use a citronella candle in the evening, though I'm not sure how effective these really are. And we make sure we keep the bedroom doors closed at all times - I can ignore them during the day, but I don't want to sleep with 'em!
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