Several questions come to mind.
What is your water temperature?
The DLFC, 25 does not make any sense, it should be 350 (3.50 gpm) with another number on it, ignore the other number.
The DLFC is set according to several factors. Does the system have the turbulator? Does it have a top screen? Water temperature?
The 12 x 48 tank is undersized, but since you are not using a gravel bed, your 50% freeboard capacity tank size would be 1.83 Cu. Feet. Still undersized for 2 cu. ft. A 12x52 is slightly undersized, but it is closer than the 12x48.
You need to get a real test kit, not a pool supply kit. A Hach 5B is the preferred kit, especially if you want to DIY. When yours comes in, let us know what it tests at. For a more accurate test, you may want to cut the sample in half with pure water. The Hach 5 B has limits, but cutting the sample works well.
Your settings are way off, you will have hard water the way it is programmed. Use this guide to get you started, but put the capacity down to 44 to accomodate for the gravel-less design and the lost resin.
In order to set the reserves, etc, how many people are in your house?
This will get you started. Let us know what your Hach 5B says your actual hardness is.