App Memory Hog Problem I swipe apps closed and they still appear to be using memory. Then I use task kill, but I can immediately refresh and they're open again. So I goto manage apps and force stop. Once again if I click back and go back into the app setting it's open again! Why is this and how can I stop it? It's mostly system apps I don't want/need and I'm afraid to uninstall them and possibly wreck my phone. Already had too many problems fixing errors because of just that.
It seems you're not "getting" how Android manages the apps.

Note: do not use task killers! There's an extensive Q&amp;A on this 

When you launch the app, it appears in the foreground, note, I am not getting into developer specifics about life-cycle of apps themselves.

There are two scenarios: 


When you press back, depending on said app, it will either go into the background, Android will eventually reclaim the memory occupied by the app.
A high priority app that appears, incoming calls is one prime example of this, Android will push the app behind, and bring forward the dialer screen where you can either lift the handset to engage or cancel the ringing.


To further embellish more:


There is a background app, called a service that is running intermittently, perhaps, polling on checking a website, Google Play Services is a prime example of it, and if there's any app update, the service will trigger the package manager to download the update and proceed, in the background.


That is primarily the reason why you should not force-stop an app, because, they may have a service running and killing that will only re-start the service which has a knock-on effect, more CPU cycles wasted in bringing up the service again, and therefore wasting yet more battery juice in the process.

Also, to force-stop an app can actually induce bad behaviour on the app itself, what if it's saving data or querying a backend content-provider, terminating it can lead to corruption or mis-behaviour. Again, this statement is only a brief example which is beyond scope of site, i.e. relating to developer in how to handle the situation in event of force-stop.


  they still appear to be using memory


"appear" is the keyword, give it a few minutes, Android will run a sweep across the memory and reclaim it if apps are inactively running or not using in fact, that memory sweep is carried out on a regular basis very actively.

At the end of the day, Android does a pretty darn good job in reclaiming memory so should not interfere with that process.