Normally you want roughly 70-30 mixture. 70 distilled water and 30 glycol. Your temp of glycol should be set low like 45f. Can be set lower if cold crashing of course but while fermenting at 66f a 45f glycol is fine.
You have TC's for the glycol reservoir and the fermenter correct? Your TC on the fv should be set to correct fermentation temp so when it goes higher it kicks on your glycol pump.
That will cool your wort , but increase the temp in your glycol chiller . That temp probe picks that up and signals the chiller motor to kick on cooling the glycol solution.
Your beer isn't ruined just yet so don't dump it.