In some states grandparents have more rights than they do in Florida, where you only have visitation rights if DCF is involved. Because the children have been in Colorado, that is the state that will likely have jurisdiction of them. That means it will depend on Colorado grandparent laws.
To add to previous answers, as the children appear to be in Florida, there are no "grandparents rights" (due to a change in law a few years back) unless (1) there is an ongoing dependency proceeding and (2) the children are NOT in the home with a parent. Given the facts as you lay them out, there does not appear to be a dependency proceeding ongoing at this time and the children are with a parent. While you may wish to directly consult with an attorney, it does not appear, under Florida law, that you have a legal basis to enforce visitation.
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