You are right. It is fine to not have a filter if you do 100% water changes weekly. However, it is very dangerous to improperly use a filter. You can either have a tank with no filter or have a tank with a filter on 24/7. You can't have a tank with a filter you turn off and on. It has to be one or the other. If you don't want to run the filter continously, then take it out of the set up all together. If you want to use a filter, but the flow is too high, then baffle it.ive always read that not having a filter is fine. i have a 5.5 gallon tank so i just do water changes every week
The way I baffle my filters is a mix of two methods. On the intake tube I stick on a piece of filter sponge. I cut a little X in the middle with a knife and then stick the tube in the sponge. For the out let, I use the water bottle method found on this sticky. http://www.bettafish.com/showthread.php?t=30139
If you still have trouble with the current then the filter is too strong.
Edit: I should mention that I have a HOB filter. If you have a canister filter, then you baffle the intake with aqaurium sponge by cutting a piece big enough to cover all the grates and holding it in place with a rubber band. The water bottle baffle still works for both.