I'm pretty new to TC but have had good success with sterilization so far (excluding some cases where I made obvious mistakes). When you spray your tank down, make sure to use a generous amount and to let it sit for a minute or two. Spraying it on and then immediately wiping it off will not kill everything. It is a good idea to routinely clean the entire area too and you might try a 10% bleach solution in your tank (but watch out for the fumes). Make sure you're washing your hands & forearms before starting and avoid moving them directly over your cultures where bacteria can fall off of you onto them.
I also use a fish tank and for flaming tools, I use this as a poor-man's touch-o-matic bunsen burner
(it is sold under a few different brand names). It's nice because the ignition button is on the top so you can start and stop it with one hand. I chose this over an always-on burner because that would create air circulation in the tank or you would have to move your tools outside the tank to flame them. It has worked well so far. Just be careful of having a flame in the enclosed tank with alcohol & alcohol fumes. I also taped off the air vent in the room I use to make sure there's no air movement in the room.
By the way, are you using any antibiotics/antifungals/PPM in your media?