We have no power today. I've picked up a battery powered aerator (hopefully just no power for one day). Does anyone know how long a fully stocked tropical tank can go for with no surface agitation? I've assumed 4 to 6 hours but don't know. I've just realised both of us are working today and will be out (should of tried the aerator on weekend to see what the life is but we also have the pest control coming in another month and I think I will leave tank switched off for that for as long as possible). Many thanks.