i have roughly 20 30 lbs of live rock. My tank has been running for a few months now
This should be sufficient to handle the bio load of a 30 gal
tank, although yours is soon to be overcrowded as soon as you angel and puffer grow larger.
The problem with mechanical filtration is it collects debris (doing what it is designed to do) and then constantly recirculates your water through it. As it rots it adds to the bio load. Unless you are extremely faithful in changing your filter media, this is what will occur. The whisper filter pad is useful for short periods of activated charcoal use but little else. Removing the filter pad will keep you from recirculating your water through rotting food and poop.
Since you may not have quite enough bio mass in the 20-30 lbs of LR
for your bioload, I would suggest removing the mechanical filter material (which I think your internal filter has) from your fluval and replace it with some bioballs or similar media to help with the bioload.
I am thinking of getting some Nassarius Snails and a few Cerith Snails to handle the fish waste and left over food at the bottom of the tank, i was wondering if the puffer would pick on or even eat the snails???
Your puffer will probably eat them. If you get some sand for your substrate, it will become populated by detritus munching worms to help rid your tank of uneaten food and fish waste.
Of course there is more than one way to run a reef tank but in mine, there is no mechanical filtration, even in the puffer tank (which has a sand bed).