I am new to the winemaking process and put my wine into 5 gallon carboy but it did not fill it to top. after about 2 weeks of fermenting i have notice what appers to be mold growing in the neck. DiD not know carboy had to be full with as little air space on it. so there was about 8 inches of air in it with airloc on top. is there anything i can do other than throw it out. Never came across anything that said to fill it up.