We have two toilets connected to septic system. One is fine the other flushes perfectly well but there is a sweet smelling odour from the toilet vent in the floor and when shine torch down can see crusty solids. Have tried hosing for several hours, all manner of septic enzymes, even when solids disappear smell remains. Do we need to get a plumber out to investigate??
I dont know what kind of vent you are talking about but you should not see water in a toilet vent that is installed properably, ehither your tank is stopped up are the line from toilet is stopped up, hard to say when you are not there, call a Lic. Plumber and have him look at it let me know.