The pow() function will bite you in the ass, too. It expects float arguments and produces a float output. Raising a value to a power of two using pow() is incredibly wasteful. A bit shift will be orders of magnitude faster, if the value is a integer. If not, simply multiplying by the value is faster.
Of course, you are storing an integer value in a float, so you will have problems deciding whether to treat seconds as an int or a float.