Coolant slowly leaking?

So recently I've been having the infamous coolant leaking issue. I took it to the mechanic and did a pressure test on the cooling system. Turns out my hoses wasn't put in tightly and securely enough. Other than that, it seems there were no other leaks.



The day after the coolant levels drop much less but still probably 1/4 cup a day or so. What do you guys think this could be? Any input would be awesome, thanks.