New bathroom/Leaky shower pan

So I installed new blue boards, new diverter in the wall and new shower pan. Now we just moved in and started using the shower and theppl downstairs are saying that there is a slight leak. I looked in the drain and it appears there may be a need for some silicone added in there because the pvc pipe going into the drain is slightyly smaller. Does anyone have any info on shower pans and drains or any info on using silicone the drain or if the pvc not fitting perfectly is normal? HELP ME. I need help so I can shower

o and i forgot to include, free steroids to ppl who help

If your going to use a caulk use something like this http://www.homedepot.com/cmc_upload/...s/107702_4.jpg

The reason to use silicone, is because its flexible and its completly water proof

I would go to home depot and ask them for help.

yeah I am going there to get my goods but thought I would do my part and research this a bit. My boy is a plumber and he told me to use clear caulk which is silicone