edited to say--someone else started this post but their post has disappeared--this is my answer to whatever it was they asked ;)

i'm not familar with that formula

but here's some possible helps:

https://www.lorannoils.com/p-8756-icicle-candy.aspx

https://www.lorannoils.com/p-8757-coal-candy.aspx

of course hot sugar and hot glass can be extremely dangerous use caution--be safe!

and isomalt can be hazardous to some tummies so i like to recommend sugar

That's too much corn syrup, you don't need that much. It probably didn't get hot enough in the microwave either. You need to get a sugar thermometer to make sure it's getting to 300 degrees. Just use 1 cup of sugar, 1/4 cup corn syrup and a little water, then heat it to about 300, take it off the stove and pour it into the molds. Make sure that the molds are heatproof! Don't stir the sugar while it's cooking or it could crystallize.

AHow long until its completely hard? Should I put it in fridge? Will it melt once its put on cake? Thank you so much!

It needs to totally cool off before you try to take them out of the mold. It will take a while if they're regular ice cube sized, since those are pretty thick, but putting them in the fridge will speed it up. Are you just using ice cube trays for the mold? Make sure to spray a little cooking spray inside to grease the mold so that they come out easier.