#1 STOP FEEDING the anemone. It needs light and should get whatever else it needs from the normal tank feedings. LTAs expend a lot of energy to digest large meals like silversides. Overfeeding them can lead to the problems you are seeing as well as the complete lack of lighting.
LTA's get BIG. Mine took up an entire corner of my tank and was about growing out of the tank before it perished.
As for test kits, don't bother with any test strips. They may be fine for a swimming pool, but not for a tank. Get good quality liquid test kits and a dosing syringe from the drugstore to measure the water sample to be tested.
Personally I like Salifert test kits for the sharp color change to give me a reading.