I think that second article will shed a lot of light on this issue for you. See, when you pull out that cartridge and throw it away, you're throwing away a lot of your beneficial bacteria along with it. There are much better HOB filters, such as Aquaclears, which allow you to combine biological filtration (this is the ceramic media), mechanical filtration (fine sponges to trap particles) and chemical filtration (this is the carbon).
It's really not necessary to run carbon unless you're actually trying to remove something from the water. Carbon generally absorbs nasties for about a month, and then it needs to be replaced. Therein lies the inherent problem in Whisper-type filters -- you're replacing carbon that you really probably didn't need to run. However, in that thirty days, the carbon has turned into a surface on which your biological bacteria has grown. Now, you have to remove the whole bag and throw it away, thus throwing away the majority of your bacteria, and setting yourself up for yet another ammonia spike.
Adding a sponge filter to your tank is an easy way to protect and maintain a colony of biological bacteria. They're really cheap, and really easy to use. You can use it in addition to the HOB you already run.
As for your fish, they may make it, and they may not. The best thing you can do, as I said earlier, are huge water changes in order to keep the Ammonia as low as possible.