WillC said:Rebecca - You are looking so carefully at your Monstera that you are losing sight of its overall good health.
The only yellow in the photo is the remainder of a dead leaf stem that you removed. You should remove what remains. It is quite normal for some older, lower leaves to yellow as the plant continues to add healthy new growth on top. The minor brown edges and spots are also normal and can be ignored.
No sign of pests or nitrogen deficiency. Fluoride in the concentration used in tap water is not a cause for concern with your plants.