The recommended level is a range. One goal is to never go lower than the low end of the range. The lowest FC normally gets is in the early evening, so that is a good time to check to make sure you are not going lower than the low end of the range. The high end of the range is more of a guideline, raise FC to around there in the morning (or the night before) and you should still be able the minimum by evening. But that needs adjusting based on your specific pool, sometimes a little higher sometimes a little lower.
Hope that helps.