Collecting Late Fees

[Codey Yingling]

My brother and I own a duplex in Lakeland FL.  Our late fee stated in the contract is 10% of the rent.  This comes into effect if the rent is not paid before the 5th of each month(4 day grace period after the 1st) plus an additional $25/day until rent is paid.  Is this to steep of late fees?  I really want to drive home the importance of making payments on time, however I'm brand new and also don't want to overkill.  Would love to hear some thoughts from others and how you deal with late fees.  As well as the best practice to enforce these fees and make sure we receive them.  Open for suggestions.