Gurgling or condensation inside the bell: Over wicking or filler material too much close to the lips of the bell can usually cause that combined with a chain
vaping style. Push the filler a bit downwards and blow
through the air vents to get rid of the excessive liquid gathered in the bell or blow
through the bottom part of the body to drive the condensation out via the drip tip. Check you filler and wick too. Moreover, when the battery is weak in relation to the resistance, the vaporisation is done partially and condensation is gathered into the bell.
The topper is not necessary in the silica builds, because you have to be very careful about the thickness of your wick, while a simple loop makes the job easy. It is an extra accessory for certain cotton builds, not all.