If your tea did start to grow a SCOBY on it, taste it. If it tastes tart or vinegary, I would make a new batch of sweet tea to add to your current tea and jar in order to fill it up. Looks like you need about 1/2 gallon. So make black tea using 4 tea bags, add 1/2 cup of sugar and, once cooled to room temperature, add it to your jar and cover. If everything is healthy, it should form a new SCOBY on the top of the liquid. After about a week to 10 days, begin tasting it. Once it reaches the level of tartness/sweetness you like, drain 3/4 of it to drink, make a new batch of sweet tea and add it the jar, remaining kombucha (starter tea) and SCOBY and repeat the process.