Thoroughly check the whole drainage line and the septic tanks for any unnoticed holes or gaps through which mosquitoes may enter the tank sensing the gas that is emitted from it.
Solar Mosquito Destroyer – Operational Manual
Drill a one inch hole on the covering slab of the tank at the end where the inlet from the drainage line opens into the tank.
Place the device on the covering slab of the tank with the support of two or three layers or bricks and connect the gas inlet tube of the device to the hole the hole drilled.
The gas inlet tube should be connected to the hole drilled in such a way that the inner end of the tube should not elongate into the tank.